Light-emitting element including intermediate connection and branches

ABSTRACT

A light-emitting element includes a light-emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first contact electrode and a second contact electrode located on the light-emitting structure, and respectively making ohmic contact with the first conductive semiconductor layer and the second conductive semiconductor layer; an insulation layer for covering a part of the first contact electrode and the second contact electrode so as to insulate the first contact electrode and the second contact electrode; a first electrode pad and a second electrode pad electrically connected to each of the first contact electrode and the second contact electrode; and a radiation pad formed on the insulation layer, and radiating heat generated from the light-emitting structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent document is a continuation of U.S. patent application Ser.No. 15/409,306, filed on Jan. 18, 2017, which is a continuation-in-partof and claims priorities to, and benefits of, International PatentApplication No. PCT/KR2016/001255, filed on Feb. 4, 2016, which claimspriorities to, and benefits of, Korean Patent Application No.10-2015-0022603, filed on Feb. 13, 2015, Korean Patent Application No.10-2015-0023752, filed on Feb. 17, 2015, Korean Patent Application No.10-2015-0037560, filed on Mar. 18, 2015, Korean Patent Application No.10-2015-0073596, filed on May 27, 2015, Korean Patent Application No.10-2015-0073598, filed on May 27, 2015, and Korean Patent ApplicationNo. 10-2015-0167920, filed on Nov. 27, 2015, which are herebyincorporated by reference for all purposes as if fully set forth herein.

TECHNICAL FIELD

Exemplary embodiments of the present document relate to a light emittingelement or a light emitting diode. For example, some embodiments of thepresent document relate to a light emitting element having improvedluminous efficacy and a light emitting diode.

BACKGROUND

With increasing demand for small, high-power light emitting elements,demand for flip-chip type large-area light emitting elements having goodheat dissipation efficiency is also increasing. In a flip-chip typelight emitting element, since electrodes are directly bonded to asecondary substrate, a wire for supply of external power source is notused, thereby providing better heat dissipation efficiency than alateral type light emitting element. That is, since heat is transferredto the secondary substrate side even upon application of high densitycurrent to the flip-chip type light emitting element, the flip-chip typelight emitting element can be used as a high power light source.

On the other hand, for miniaturization of light emitting elements, thereis increasing demand for a chip-scale package which allows a lightemitting element to be used as a package by eliminating a separateprocess of packaging the light emitting element in a housing. For theflip-chip type light emitting element, the electrodes act like leads ofthe package and thus can be advantageously applied to the chip-scalepackage.

In fabrication of a light emitting element using a chip-scale package,high density current can be applied to the chip-scale package. Recently,with increasing demand for high power products, drive current applied tothe chip-scale package is also increasing. As the drive current appliedto the chip-scale package increases, heat generated from a lightemitting diode chip also increases, thereby causing thermal stress tothe light emitting element. Moreover, junction temperature is alsoincreased due to the increased heat, thereby causing deterioration inreliability of the light emitting element.

In addition, a light emitting element can be manufactured by disposing aplurality of chip-scale package type light emitting cells connected toeach other in series or in parallel on a substrate. In the structure ofthe light emitting cell realized using the plurality of light emittingcells, a non-luminous region is formed between the light emitting cells,thereby causing poor luminous efficacy at the center of the lightemitting element.

To fulfill recent demand for high power products, various studies forincreasing luminous efficacy of the chip-scale package have been carriedout. Even in the case of fabricating a light emitting element usingplural light emitting cells, technology for maximizing luminous efficacyof the light emitting element is required.

In application of a plurality of light emitting elements connected toeach other in series to a headlight of an automobile, relatively highvoltage can be applied to opposite ends of the plurality of lightemitting elements connected to each other in series. When the lightemitting elements connected in series do not have forward voltagecharacteristics, an excessively high voltage can be applied to a lightemitting diode having low forward voltage, whereby the light emittingelement can exhibit low stability, thereby causing deterioration inproduct reliability.

SUMMARY

Exemplary embodiments disclosed in the present document provide a lightemitting element, which is fabricated using a plurality of lightemitting structures and secures good reliability and high luminousefficacy upon application of high power.

Exemplary embodiments disclosed in the present document provide a lightemitting element, which includes a plurality of light emittingstructures connected to each other in series and secures high intensityof light emitted from the center thereof, and a light emitting diode.

Exemplary embodiments disclosed in the present document provide a lightemitting element which has improved current spreading performance.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a light emitting structure including afirst conductive type semiconductor layer, a second conductive typesemiconductor layer, and an active layer interposed between the firstconductive type semiconductor layer and the second conductive typesemiconductor layer; a first contact electrode and a second contactelectrode disposed on the light emitting structure and forming ohmiccontact with the first conductive type semiconductor layer and thesecond conductive type semiconductor layer, respectively; an insulationlayer partially covering the first contact electrode and the secondcontact electrode to insulate the first contact electrode and the secondcontact electrode; a first electrode pad and a second electrode padelectrically connected to the first contact electrode and the secondcontact electrode, respectively; and a heat dissipation pad formed onthe insulation layer and dissipating heat from the light emittingstructure, the heat dissipation pad having at least three planes exposedto the outside.

In some implementations, at least one of the first electrode pad and thesecond electrode pad may be formed on the insulation layer and disposedat one side on a surface of the insulation layer.

In some implementations, the first electrode pad and the secondelectrode pad may be separated from each other on the insulation layer,and the heat dissipation pad may be formed on the insulation layer to bedisposed between the first and second electrode pads.

In some implementations, the light emitting element may include at leasttwo first electrode pads and at least two second electrode pads, and theat least two first electrode pads and the at least two second electrodepads may be formed on the insulation layer to be separated from eachother thereon.

In some implementations, the heat dissipation pad may be formed on theinsulation layer to be disposed between the first electrode pad and thesecond electrode pad. Alternatively, the light emitting element mayinclude at least two heat dissipation pads having at least three planesexposed to the outside. The at least two heat dissipation pads may beseparated from each other.

In some implementations, the insulation layer may include a firstinsulation layer formed between the first and second contact electrodesto cover a portion of the second contact electrode, and having a firstopening and a second opening partially exposing the first conductivetype semiconductor layer and the second contact electrode, respectively;and a second insulation layer covering a portion of the first contactelectrode partially covering the first insulation layer, and having athird opening and a fourth opening partially exposing the first contactelectrode and the second contact electrode, respectively.

In some implementations, the first electrode pad may be electricallyconnected to the first contact electrode through the third opening andthe second electrode pad may be electrically connected to the secondcontact electrode through the fourth opening.

In some implementations, the light emitting structure may include aplurality of holes partially exposing the first conductive typesemiconductor layer and the first contact electrode may be electricallyconnected to the first conductive type semiconductor layer through theplurality of holes.

In some implementations, each of the first electrode pad and the secondelectrode pad may include at least one of Cu, Pt, Au, Ti, Ni, Al or Ag,and the heat dissipation pad may include at least one of Cu, Pt, Au, Ti,Ni, Al or Ag.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a plurality of light emittingstructures electrically connected to each other; a first electrode padelectrically connected to one of the light emitting structures; a secondelectrode pad electrically connected to another light emitting structureamong the plurality of light emitting structures; and a heat dissipationpad formed on the plurality of light emitting structures and dissipatingheat from the plurality of light emitting structures, the heatdissipation pad having at least three surfaces exposed to the outside.

In some implementations, the light emitting structure may include: afirst conductive type semiconductor layer; a second conductive typesemiconductor layer; an active layer interposed between the firstconductive type semiconductor layer and the second conductive typesemiconductor layer; a first contact electrode and a second contactelectrode disposed on the second conductive type semiconductor layer andforming ohmic contact with the first conductive type semiconductor layerand the second conductive type semiconductor layer, respectively; and aninsulation layer partially covering the first contact electrode and thesecond contact electrode to insulate the first contact electrode and thesecond contact electrode.

In some implementations, the first electrode pad and the secondelectrode pad may be electrically connected to the first contactelectrode and the second contact electrode, respectively, and the firstand second electrode pads and the heat dissipation pad may be formed onthe insulation layer. The plurality of light emitting structures may beconnected to each other in series.

In some implementations, a cross-sectional area of the heat dissipationpad may be 50% or more the cross-sectional area of the light emittingelement in a plan view.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; one ormore second light emitting cells disposed coplanar with the first lightemitting cell; a first electrode pad formed on the first light emittingcell or on the second light emitting cells, and electrically connectedto the first light emitting cell and one of the second light emittingcells; and a second electrode pad formed on the first light emittingcell or on the second light emitting cells, and electrically connectedto the first light emitting cell and the other second light emittingcell, wherein the first light emitting cell is disposed at a center ofthe light emitting element and the second light emitting cells aredisposed to surround the first light emitting cell.

In some implementations, the first light emitting cell and the secondlight emitting cells may be electrically connected to each other. Thefirst light emitting cell and the second light emitting cells may beelectrically connected to each other in series.

In some implementations, each of the first light emitting cell and thesecond light emitting cells may include: a light emitting structureincluding a first conductive type semiconductor layer, a secondconductive type semiconductor layer and an active layer interposedbetween the first conductive type semiconductor layer and the secondconductive type semiconductor layer; a first contact electrode and asecond contact electrode disposed on the light emitting structure andforming ohmic contact with the first conductive type semiconductor layerand the second conductive type semiconductor layer, respectively; and aninsulation layer partially covering the first contact electrode and thesecond contact electrode to insulate the first contact electrode and thesecond contact electrode, the first electrode pad and the secondelectrode pad being electrically connected to the first contactelectrode and the second contact electrode, respectively.

In some implementations, at least one of the first electrode pad and thesecond electrode pad may be formed on the insulation layer. Theinsulation layer may include a first insulation layer formed between thefirst and second contact electrodes to cover a portion of the secondcontact electrode, and having a first opening and a second openingpartially exposing the first conductive type semiconductor layer and thesecond contact electrode, respectively; and a second insulation layercovering a portion of the first contact electrode partially covering thefirst insulation layer, and having a third opening and a fourth openingpartially exposing the first contact electrode and the second contactelectrode, respectively.

In some implementations, the first electrode pad may be electricallyconnected to the first contact electrode through the third opening andthe second electrode pad may be electrically connected to the secondcontact electrode through the fourth opening.

In some implementations, the light emitting structure may include aplurality of holes partially exposing the first conductive typesemiconductor layer and the first contact electrode may be electricallyconnected to the first conductive type semiconductor layer through theplurality of holes.

In some implementations, each of the first electrode pad and the secondelectrode pad may include at least one of Cu, Pt, Au, Ti, Ni, Al and Ag.The first light emitting cell may have a circular shape or a polygonalshape having at least four angles.

In accordance with one exemplary embodiment of the present disclosure, alight emitting diode includes: a light emitting element including afirst light emitting cell, one or more second light emitting cellsdisposed coplanar with the first light emitting cell, and first andsecond electrode pads electrically connected to the first light emittingcell and one and another light emitting cells among the second lightemitting cells, respectively; and a lens dispersing light emitted fromthe light emitting element, wherein the first light emitting cell isdisposed at the center of the light emitting element and the secondlight emitting cells are disposed to surround the first light emittingcell.

In some implementations, the lens may include a lower surface defining alight incidence plane on which light is incident; and an upper surfacehaving a circular or modified circular cross-sectional curvature anddefining a light exit plane. The lens may include a lower surfacedefining a light incidence plane on which light is incident; an uppersurface reflecting the incident light; and a side surface formed betweenthe lower surface and the upper surface and allowing the light reflectedby the upper surface to exit therethrough.

In some implementations, the first light emitting cell and the secondlight emitting cells may be electrically connected to each other and thefirst light emitting cell may have a circular shape or a polygonal shapehaving at least four angles.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; one ormore second light emitting cells disposed coplanar with the first lightemitting cell and electrically connected to the first light emittingcell; a first electrode pad formed on the first light emitting cell orthe second light emitting cells and electrically connected to the firstlight emitting cell and one of the second light emitting cells; a secondelectrode pad formed on the first light emitting cell or the secondlight emitting cells and electrically connected to the first lightemitting cell and another second light emitting cell among the secondlight emitting cells; and a heat dissipation pad formed on the firstlight emitting cell and the second light emitting cells and dissipatingheat from the first light emitting cell and the second light emittingcells, wherein the first light emitting cell is disposed at the centerof the light emitting element and the second light emitting cells aredisposed to surround the first light emitting cell.

In some implementations, the heat dissipation pad may have at leastthree planes exposed to the outside.

In some implementations, each of the first light emitting cell and thesecond light emitting cells may include: a light emitting structureincluding a first conductive type semiconductor layer, a secondconductive type semiconductor layer and an active layer interposedbetween the first conductive type semiconductor layer and the secondconductive type semiconductor layer; a first contact electrode and asecond contact electrode disposed on the light emitting structure andforming ohmic contact with the first conductive type semiconductor layerand the second conductive type semiconductor layer, respectively; and aninsulation layer partially covering the first contact electrode and thesecond contact electrode to insulate the first contact electrode and thesecond contact electrode, the first electrode pad and the secondelectrode pad being electrically connected to the first contactelectrode and the second contact electrode, respectively.

In some implementations, the insulation layer may include a firstinsulation layer formed between the first and second contact electrodesto cover a portion of the second contact electrode, and having a firstopening and a second opening partially exposing the first conductivetype semiconductor layer and the second contact electrode, respectively;and a second insulation layer covering a portion of the first contactelectrode partially covering the first insulation layer, and having athird opening and a fourth opening partially exposing the first contactelectrode and the second contact electrode, respectively.

In some implementations, at least one of the first electrode pad, thesecond electrode pad and the heat dissipation pad may be formed on thesecond insulation layer, the first electrode pad may be electricallyconnected to the first contact electrode through the third opening, andthe second electrode pad may be electrically connected to the secondcontact electrode through the fourth opening.

In some implementations, each of the first electrode pad, the secondelectrode pad and the heat dissipation pad may include at least one ofCu, Pt, Au, Ti, Ni, Al and Ag.

In some implementations, the first electrode pad, the second electrodepad and the heat dissipation pad may be separated from one another, andthe first light emitting cell may have a circular shape or a polygonalshape having at least four angles.

In accordance with one exemplary embodiment of the present disclosure, alight emitting diode includes: a light emitting element including afirst light emitting cell, one or more second light emitting cellsdisposed coplanar with the first light emitting cell, and first andsecond electrode pads electrically connected to the first light emittingcell and one and another light emitting cell among the second lightemitting cells, respectively, and a heat dissipation pad formed on thefirst light emitting cell and the second light emitting cells todissipate heat from the light emitting cells; and a printed circuitboard on which the light emitting element is mounted, the printedcircuit board including a board body dissipating heat transferredthrough the heat dissipation pad; and a lead portion formed on the boardbody and electrically connected to the first and second electrode pads.

In some implementations, the board body may contact the heat dissipationpad and the printed circuit board may further include a dissipationportion formed on the board body and contacting the heat dissipationpad.

In some implementations, the lead portion and the dissipation portionmay be insulated from each other.

In some implementations, the printed circuit board may further includean insulation portion interposed between the board body and the leadpart.

In some implementations, the light emitting diode may further include alens disposed above the light emitting element and dispersing lightemitted from the light emitting element, wherein the lens may include aphosphor converting a wavelength of the light emitted from the lightemitting element.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; a secondlight emitting cell disposed coplanar with the first light emitting celland electrically connected to the first light emitting cell; a thirdlight emitting cell disposed coplanar with the first and second lightemitting cells and electrically connected to the second light emittingcell; a first electrode connection electrically connecting the firstlight emitting cell to the second light emitting cell; and a secondelectrode connection electrically connecting the second light emittingcell to the third light emitting cell, wherein the first electrodeconnection and the second electrode connection are disposed in adiagonal direction with reference to the second light emitting cell, aredisposed on the second light emitting cell and the third light emittingcell, respectively, and cover side surfaces of the second and thirdlight emitting cells.

In some implementations, the first electrode connection and the secondelectrode connection may be disposed on different sides with referenceto the second light emitting cell, respectively.

In some implementations, the first electrode connection may be placed ata corner of one surface of the second light emitting cell and the secondelectrode connection may be placed at a corner of a surface adjacent tothe one surface of the second light emitting cell.

In some implementations, the first electrode connection may be disposedon the second light emitting cell and the second electrode connectionmay be disposed on the third light emitting cell.

In some implementations, each of the first to third light emitting cellsmay include: a light emitting structure including a first conductivetype semiconductor layer, a second conductive type semiconductor layer,and an active layer interposed between the first conductive typesemiconductor layer and the second conductive type semiconductor layer;a first contact electrode and a second contact electrode disposed on thelight emitting structure and forming ohmic contact with the firstconductive type semiconductor layer and the second conductive typesemiconductor layer, respectively; and an insulation layer partiallycovering the first contact electrode and the second contact electrode toinsulate the first contact electrode and the second contact electrode.

In some implementations, the insulation layer may include a firstinsulation layer covering the second contact electrode and having afirst opening and a second opening partially exposing the firstconductive type semiconductor layer and the second contact electrode,respectively; and a second insulation layer covering the first contactelectrode covering the first insulation layer, and having a thirdopening and a fourth opening partially exposing the first contactelectrode and the second contact electrode, respectively.

In some implementations, the first opening may be provided in plural soas to allow the first contact electrode to form ohmic contact with thefirst conductive type semiconductor layer through a plurality of firstopenings, and each of the first and second electrodes connection may beformed between the plurality of first openings of the second and thirdlight emitting cells.

In some implementations, the first insulation layer may include apre-insulation layer partially covering an upper surface or a sidesurface of the light emitting structure; and a main insulation layercovering the pre-insulation layer and the second contact electrode.

In some implementations, the first contact electrode of the first lightemitting cell may extend to an upper surface of the light emittingstructure of the second light emitting cell to form ohmic contact withthe second contact electrode.

In some implementations, the light emitting diode may further include amesa including the second conductive type semiconductor layer and theactive layer; and a third insulation layer partially covering an uppersurface of the mesa.

In some implementations, the second contact electrode may form ohmiccontact with the second conductive type semiconductor layer on the mesa.

In some implementations, the light emitting diode may further include asubstrate disposed under the light emitting structure, and the substratemay include a plurality of patterns formed on an upper surface thereof.

In some implementations, the first contact electrode of the first lightemitting cell may extend to an upper surface of the second lightemitting cell to cover one side of the second light emitting cell, andthe first contact electrode of the second light emitting cell may extendto an upper surface of the third light emitting cell to cover one sideof the third light emitting cell.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; a secondlight emitting cell disposed coplanar with the first light emitting celland electrically connected to the first light emitting cell; and aplurality of electrode connections electrically connecting the firstlight emitting cell to the second light emitting cell, wherein theplurality of electrode connections extends from the first light emittingcell and is disposed on the second light emitting cell to cover aportion of an upper surface of the second light emitting cell, theplurality of electrode connections being disposed along one side of thesecond light emitting cell in a plan view.

In some implementations, the first and second light emitting cells maybe disposed such that one side of the first light emitting cell isadjacent to one side of the second light emitting cell in the plan view.

In some implementations, the electrode connections may be arranged atthe one side of the second light emitting cell facing the one side ofthe first light emitting cell.

In some implementations, the first light emitting cell and the secondlight emitting cell may be disposed such that one corner of the firstlight emitting cell is adjacent to one corner of the second lightemitting cell in a plan view, and the electrode connections may extendfrom the first light emitting cell along the one side of the secondlight emitting cell.

In some implementations, each of the first and second light emittingcells may include a light emitting structure including a firstconductive type semiconductor layer, a second conductive typesemiconductor layer, and an active layer interposed between the firstconductive type semiconductor layer and the second conductive typesemiconductor layer; a first contact electrode and a second contactelectrode disposed on the light emitting structure and forming ohmiccontact with the first conductive type semiconductor layer and thesecond conductive type semiconductor layer, respectively; and aninsulation layer partially covering the first contact electrode and thesecond contact electrode to insulate the first contact electrode and thesecond contact electrode.

In some implementations, the insulation layer may include a firstinsulation layer covering the second contact electrode and having afirst opening and a second opening partially exposing the firstconductive type semiconductor layer and the second contact electrode,respectively; and a second insulation layer covering the first contactelectrode covering the first insulation layer, and having a thirdopening and a fourth opening partially exposing the first contactelectrode and the second contact electrode, respectively.

In some implementations, the first insulation layer may include apre-insulation layer partially covering an upper surface or a sidesurface of the light emitting structure; and a main insulation layercovering the pre-insulation layer and the second contact electrode.

In some implementations, the first contact electrode of the first lightemitting cell may extend to an upper surface of the light emittingstructure of the second light emitting cell and form ohmic contact withthe second contact electrode.

In some implementations, each of the first and second light emittingcells may further include a mesa including the second conductive typesemiconductor layer and the active layer, and the first insulation layermay include a pre-insulation layer partially covering an upper surfaceof the mesa.

In some implementations, the second contact electrode may form ohmiccontact with the second conductive type semiconductor layer on the mesa.

In some implementations, the light emitting element may further includea substrate disposed under the light emitting structure, and thesubstrate may include a plurality of patterns formed on an upper surfacethereof.

In some implementations, some patterns formed on the substrate andexposed instead of being covered by the light emitting structure mayhave a smaller size than the remaining patterns covered by the lightemitting structure.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; a secondlight emitting cell disposed coplanar with the first light emitting celland adjacent thereto in a first direction; a plurality of contact holesdisposed on the first light emitting cell and the second light emittingcell to be separated from each other; and a first electrode connectionelectrically connecting the first light emitting cell to the secondlight emitting cell, wherein the first electrode connection includes afirst-1 electrode connection disposed on the first light emitting cell;a first-2 electrode connection disposed on the second light emittingcell; and a first intermediate connection interposed between the firstlight emitting cell and the second light emitting cell and connectingthe first-1 electrode connection to the first-2 electrode connection,and wherein the first-1 electrode connection includes first-1 edgeportions placed on an edge of a first side surface of the first lightemitting cell adjacent to the second light emitting cell and on an edgeof another side surface of the first light emitting cell adjacent to thefirst side surface thereof.

In some implementations, the first light emitting cell includes a firstside surface adjacent to the second light emitting cell, a second sidesurface facing the first side surface, and a third side surface and afourth side surface disposed between the first side surface and thesecond side surface and facing each other, and the first-1 edge portionsmay be restrictively placed on edges of the first side surface and thethird side surface.

In some implementations, the first-1 electrode connection may include aplurality of first-1 branches extending from the first-1 edge portions,and the plurality of first-1 branches may include branches extendingfrom the first-1 edge portion disposed at the third side surface towardsthe second side surface, branches extending from the first-1 edgeportion disposed at the first side surface towards the second sidesurface, and first-1 branches extending from the first-1 edge portiondisposed at the first side surface towards the fourth side surface.

In some implementations, the first-1 branches may be disposed parallelto each other and may be disposed between the contact holes on the firstlight emitting cell.

In some implementations, the light emitting element may further includea contact-hole connection connecting the contact holes arranged on thefirst light emitting cell to each other, and the contact-hole connectionmay include branches disposed between the first-1 branches and parallelto the first-1 branches.

In some implementations, the second light emitting cell may include afirst side surface adjacent to the first light emitting cell, a secondside surface facing the first side surface, a third side surfacedisposed between the first side surface and the second side surface andadjacent to the third side surface of the first light emitting cell, anda fourth side surface facing the third side surface, and the first-2electrode connection may include first-2 edge portions disposed on edgesat the first side surface of the second light emitting cell adjacent tothe first light emitting cell and at the fourth side surface of thesecond light emitting cell.

In some implementations, the first-2 electrode connection may include aplurality of first-2 branches extending from the first-2 edge portionsand the plurality of first-2 branches may be parallel to the pluralityof first-1 branches.

In some implementations, each of the first-2 branches may connect thecontact holes on the second light emitting cell to each other.

In some implementations, the light emitting element may further include:a third light emitting cell disposed coplanar with the second lightemitting cell and adjacent thereto in a first direction; a plurality ofcontact holes disposed on the third light emitting cell to be separatedfrom each other; and a second electrode connection electricallyconnecting the second light emitting cell to the third light emittingcell, wherein the second electrode connection includes a second-1electrode connection disposed on the second light emitting cell; asecond-2 electrode connection disposed on the third light emitting cell;and a second intermediate connection interposed between the second lightemitting cell and the third light emitting cell and connecting thesecond-1 electrode connection to the second-2 electrode connection, andwherein the second-1 electrode connection includes second-1 edgeportions placed on edges of the second side surface of the second lightemitting cell adjacent to the third light emitting cell and of the thirdside surface of the second light emitting cell.

In some implementations, the second-1 electrode connection may include aplurality of second-1 branches extending from the second-1 edge portionsand the second-1 branches may be parallel to the first-2 branches.

In some implementations, the third light emitting cell may include afirst side surface adjacent to the second light emitting cell, a secondside surface facing the first side surface, a third side surfacedisposed between the first side surface and the second side surface andadjacent to the third side surface of the second light emitting cell,and a fourth side surface facing the third side surface thereof, and thesecond-2 electrode connection may include second-2 edge portions placedon edges of the first side surface of the third light emitting celladjacent to the second light emitting cell and of the fourth sidesurface of the third light emitting cell.

In some implementations, the second-2 electrode connection may include aplurality of second-2 branches extending from the second-2 edge portionsand the plurality of second-2 branches may be parallel to the pluralityof second-1 branches.

In some implementations, each of the second-2 branches may connect thecontact holes on the third light emitting cell to each other.

In some implementations, the light emitting element may further include:a fourth light emitting cell including a lower semiconductor layer andan upper semiconductor layer, the fourth light emitting cell beingdisposed coplanar with the third light emitting cell and adjacentthereto in a first direction; a plurality of contact holes disposed onthe fourth light emitting cell to be separated from each other; and athird electrode connection electrically connecting the third lightemitting cell to the fourth light emitting cell, wherein the thirdelectrode connection includes a third-1 electrode connection disposed onthe third light emitting cell; a third-2 electrode connection disposedon the fourth light emitting cell; and a third intermediate connectioninterposed between the third light emitting cell and the fourth lightemitting cell and connecting the third-1 electrode connection to thethird-2 electrode connection, and wherein the third-1 electrodeconnection includes third-1 edge portions placed on edge of the secondside surface of the third light emitting cell adjacent to the fourthlight emitting cell and of the third side surface of the third lightemitting cell.

In some implementations, the third-1 electrode connection may include aplurality of third-1 branches extending from the third-1 edge portionsand disposed parallel to the second-2 branches, and the third-2electrode connection may connect the contact holes on the fourth lightemitting cell to each other while exposing the openings.

In some implementations, the light emitting element may further include:a first electrode pad and a second electrode pad, wherein the firstelectrode pad is electrically connected to the first conductive typesemiconductor layer of the first light emitting cell and is disposedover the first and second light emitting cells, and the second electrodepad is electrically connected to the second conductive typesemiconductor layer of the fourth light emitting cell and is disposedover the third and fourth light emitting cells.

In accordance with one exemplary embodiment of the present disclosure, alight emitting element includes: a first light emitting cell; a secondlight emitting cell disposed coplanar with the first light emitting celland adjacent thereto in a first direction; a plurality of contact holesdisposed on the first light emitting cell and the second light emittingcell and separated from each other; and a first electrode connectionelectrically connecting the first light emitting cell to the secondlight emitting cell, wherein the first electrode connection includes afirst-1 electrode connection disposed on the first light emitting cell;a first-2 electrode connection disposed on the second light emittingcell; and a first intermediate connection interposed between the firstlight emitting cell and the second light emitting cell and connectingthe first-1 electrode connection to the first-2 electrode connection,and wherein the first-1 electrode connection includes a plurality offirst-1 branches parallel to each other and the first-2 electrodeconnection includes a plurality of first-2 branches parallel to eachother, the first-1 branches being parallel to the first-2 branches, thefirst-1 branches and the first-2 branches being inclined with respect tothe first direction and a direction perpendicular to the firstdirection.

In some implementations, the light emitting element may further include:a third light emitting cell disposed coplanar with the second lightemitting cell and adjacent thereto in the first direction; a pluralityof contact holes disposed on the third light emitting cell to beseparated from each other; and a second electrode connectionelectrically connecting the second light emitting cell to the thirdlight emitting cell, wherein the second electrode connection includes asecond-1 electrode connection disposed on the second light emittingcell; a second-2 electrode connection disposed on the third lightemitting cell; and a second intermediate connection interposed betweenthe second light emitting cell and the third light emitting cell andconnecting the second-1 electrode connection to the second-2 electrodeconnection, and wherein the second-1 electrode connection includes aplurality of second-1 branches parallel to each other and the second-2electrode connection includes a plurality of second-2 branches parallelto each other, the second-1 branches are parallel to the second-2branches, and the second-1 branches and the second-2 branches areparallel to the first-1 branches and the first-2 branches, respectively.

In some implementations, the light emitting element may further include:a fourth light emitting cell disposed coplanar with the third lightemitting cell and adjacent thereto in the first direction; a pluralityof contact holes disposed on the fourth light emitting cell to beseparated from each other; and a third electrode connection electricallyconnecting the third light emitting cell to the fourth light emittingcell, wherein the third electrode connection includes a third-1electrode connection disposed on the third light emitting cell; athird-2 electrode connection disposed on the fourth light emitting cell;and a third intermediate connection interposed between the third lightemitting cell and the fourth light emitting cell and connecting thethird-1 electrode connection to the third-2 electrode connection, andwherein the third-1 electrode connection includes a plurality of third-1branches parallel to each other, and the third-1 branches are parallelto the second-1 branches and the second-2 branches.

In some implementations, the light emitting element may further include:a first electrode pad and a second electrode pad, wherein the firstelectrode pad is disposed over the first and second light emitting cellsand the second electrode pad is disposed over the third and fourth lightemitting cells.

According to exemplary embodiments, the light emitting element includesa heat dissipation pad configured to dissipate heat from a lightemitting structure in addition to electrodes for supplying electricpower to the light emitting structure, thereby enabling efficient heatdissipation from the light emitting element.

According to exemplary embodiments, the light emitting elements includesa plurality of light emitting structures, in which one light emittingstructure is disposed at the center of the light emitting element andother light emitting structures are disposed around the light emittingstructure disposed at the center of the light emitting element, therebyimproving the intensity of light emitted from the center of the lightemitting element.

According to exemplary embodiments, the light emitting element includesa plurality of light emitting cells electrically connected to each otherthrough electrode connections disposed at different sides of the lightemitting cells so as to allow electric current applied to the lightemitting element to be uniformly distributed to the entirety of thelight emitting cells, thereby maximizing luminous efficacy of the lightemitting element.

According to exemplary embodiments, the light emitting element includesa first contact electrode electrically connecting the light emittingcells and extending towards a light emitting cell adjacent to the firstcontact electrode to be electrically connected to a second contactelectrode of the adjacent light emitting cell so as to reflect lightemitted from a space between the light emitting cells to the outside ofthe light emitting element, thereby maximizing luminous efficacy of thelight emitting element.

According to exemplary embodiments, the light emitting element includesa plurality of light emitting cells electrically connected to each otherthrough electrode connections, which include edge portions disposed onedges of two side surfaces of a first light emitting cell, therebyenabling uniform distribution of electric current over a wide area ofthe first light emitting cell.

In addition, branches of the electrode connections are parallel to eachother on the first light emitting cell and the second light emittingcell while being inclined with respect to an arrangement direction ofthe light emitting cells, thereby improving current dispersion.

Furthermore, adjacent light emitting cells are connected to each otherin series, whereby light emitting cells exhibiting similar luminouscharacteristics can be used in one light emitting element, therebymaintaining a constant forward voltage, and the edge portions and/or thebranches are formed to achieve uniform dispersion of electric current toa plurality of light emitting cells, whereby the light emitting cellscan have a constant forward voltage, thereby improving reliability ofthe light emitting element.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a bottom view of a light emitting element according to a firstexemplary embodiment of the present document.

FIGS. 2A and 2B show cross-sectional views taken along lines A-A′ andB-B′ of FIG. 1.

FIGS. 3A and 3B are bottom views of heat dissipation pads of a typicallight emitting element and the light emitting element according to thefirst exemplary embodiment of the present disclosure.

FIG. 4 is a bottom view of a light emitting element according to asecond exemplary embodiment of the present disclosure.

FIG. 5 is a cross-sectional view taken along line C-C′ of FIG. 4.

FIG. 6 is a bottom view of a light emitting element according to a thirdexemplary embodiment of the present disclosure.

FIG. 7 is a bottom view of a light emitting element according to afourth exemplary embodiment of the present disclosure.

FIG. 8 is a bottom view of a light emitting element according to a fifthexemplary embodiment of the present disclosure.

FIG. 9 is a cross-sectional view taken along line A-A′ of FIG. 8.

FIG. 10 is a side sectional view of a light emitting diode including thelight emitting element according to the fifth exemplary embodiment ofthe present disclosure and a dome-shaped lens.

FIG. 11 is a side sectional view of a light emitting diode including thelight emitting element according to the fifth exemplary embodiment ofthe present disclosure and a total reflection type lens.

FIG. 12 is a bottom view of a light emitting element according to asixth exemplary embodiment of the present disclosure.

FIGS. 13A-13C show cross-sectional views taken along lines A-A′, B-B′and C-C′ of FIG. 12.

FIGS. 14A-14C show side sectional views of a light emitting diodeaccording to a sixth exemplary embodiment of the present disclosure.

FIG. 15 is a side sectional view of a light emitting diode including thelight emitting element according to the sixth exemplary embodiment ofthe present disclosure and a dome-shaped lens.

FIG. 16 is a side sectional view of a light emitting diode including thelight emitting element according to the sixth exemplary embodiment ofthe present disclosure and a concave lens.

FIGS. 17A-17C show side sectional views of a light emitting diodeincluding the light emitting element according to the sixth exemplaryembodiment of the present disclosure, a printed circuit board, and alens.

FIG. 18 is a plan view of a light emitting element according to aseventh exemplary embodiment of the present disclosure.

FIG. 19 is a schematic plan view of the light emitting element accordingto the seventh exemplary embodiment of the present disclosure.

FIGS. 20A-20C show cross-sectional views taken along lines A-A′, B-B′and C-C′ of FIG. 1.

FIG. 21 to FIG. 23 are analysis pictures of the light emitting elementaccording to the seventh exemplary embodiment of the present disclosure.

FIG. 24 is a plan view of a light emitting element according to aneighth exemplary embodiment of the present disclosure.

FIG. 25 is a plan view of a light emitting element according to a ninthexemplary embodiment of the present disclosure.

FIG. 26 is a schematic plan view of the light emitting element accordingto the ninth exemplary embodiment of the present disclosure.

FIGS. 27A-27C show cross-sectional views taken along lines A-A′, B-B′and C-C′ of FIG. 26.

FIG. 28 is a plan view of a light emitting element according to a tenthexemplary embodiment of the present disclosure.

FIG. 29 is a plan view of a light emitting element according to aneleventh exemplary embodiment of the present disclosure.

FIG. 30 is a plan view of a light emitting element according to atwelfth exemplary embodiment of the present disclosure.

FIG. 31 is a schematic plan view of the light emitting element accordingto the twelfth exemplary embodiment of the present disclosure.

FIG. 32 is a schematic cross-sectional view taken along line A-A′ ofFIG. 31.

FIG. 33 is a schematic cross-sectional view taken along line B-B′ ofFIG. 31.

FIG. 34 is a schematic cross-sectional view taken along line C-C′ ofFIG. 31.

FIG. 35 is a schematic cross-sectional view taken along line D-D′ ofFIG. 31.

FIG. 36 is a schematic cross-sectional view taken along line E-E′ ofFIG. 31.

FIG. 37 is a schematic cross-sectional view taken along line F-F′ ofFIG. 31.

FIG. 38 is a schematic cross-sectional view of a module including thelight emitting element according to the twelfth exemplary embodiment ofthe present disclosure.

FIG. 39 is a schematic plan view of the module including the lightemitting element according to the twelfth exemplary embodiment of thepresent disclosure.

FIG. 40 is an exploded perspective view of a lighting apparatus to whicha light emitting element according to one exemplary embodiment of thepresent disclosure is applied.

FIGS. 41A and 41B are cross-sectional views of one example of a displayapparatus to which a light emitting element according to one exemplaryembodiment of the present disclosure is applied.

FIGS. 42A and 42B are cross-sectional views of another example of thedisplay apparatus to which the light emitting element according to theexemplary embodiment of the present disclosure is applied.

FIG. 43 is a cross-sectional view of a headlight to which a lightemitting element according to one exemplary embodiment of the presentdisclosure is applied.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. Thefollowing embodiments are provided by way of example so as to facilitatethe understanding of various embodiments of the present disclosure.Accordingly, the present disclosure is not limited to the embodimentsdisclosed herein and can also be implemented in different forms. When anelement is referred to as being “disposed above” or “disposed on”another element, it can be directly “disposed above” or “disposed on”the other element, or intervening elements can be present. Throughoutthe specification, like reference numerals denote like elements havingthe same or similar functions. The term “exemplary” is used to mean “anexample of” and does not necessarily mean an ideal or a bestimplementation.

Exemplary embodiments of the present disclosure will be described indetail with reference to the accompanying drawings.

FIG. 1 is a bottom view of a light emitting element according to a firstexemplary embodiment of the present disclosure, FIG. 2A is across-sectional view taken along line A-A′ of FIG. 1, and FIG. 2B is across-sectional view taken along line B-B′ of FIG. 1.

Referring to FIG. 1 and FIGS. 2A and 2B, the light emitting element 10according to the first exemplary embodiment includes a light emittingstructure 23, a first contact electrode 31, a second contact electrode33, a first insulation layer 35, a second insulation layer 37, a firstelectrode pad 39, a second electrode pad 41, and a heat dissipation pad43.

The light emitting structure 23 includes a first conductive typesemiconductor layer 25, an active layer 27 disposed on the firstconductive type semiconductor layer 25, and a second conductive typesemiconductor layer 29 disposed on the active layer 27. The firstconductive type semiconductor layer 25, the active layer 27 and thesecond conductive type semiconductor layer 29 may include a III-V basedcompound semiconductor, for example, a nitride semiconductor such as(Al, Ga, In)N.

The first conductive type semiconductor layer 25 may include an n-typedopant (for example, Si) and the second conductive type semiconductorlayer 29 may include a p-type dopant (for example, Mg), or vice versa.The active layer 27 may include a multi-quantum well (MQW) structure andthe composition ratio of the active layer may be determined so as toemit light in a desired wavelength range.

The light emitting structure 23 may include a partially exposed regionof the first conductive type semiconductor layer 25 formed by partiallyremoving the second conductive type semiconductor layer 29 and theactive layer 27. That is, as shown in FIGS. 2A and 2B, a plurality ofholes h may be formed through the second conductive type semiconductorlayer 29 and the active layer 27 to expose the first conductive typesemiconductor layer 25. Here, the shape and arrangement of the holes hmay be modified in various ways. In the partially exposed region of thefirst conductive type semiconductor layer 25, a mesa including thesecond conductive type semiconductor layer 29 and the active layer 27may be formed by partially removing the second conductive typesemiconductor layer 29 and the active layer 27.

A growth substrate may be disposed under the first conductive typesemiconductor layer 25 of the light emitting structure 23. The growthsubstrate may be any substrate which allows growth of the light emittingstructure 23 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, or an aluminum nitride substrate. The growthsubstrate may be removed from the light emitting structure 23 using atechnique known in the art, as needed. Although not shown in thedrawings, the light emitting structure 23 may have a rough region formedon a lower surface thereof.

The first contact electrode 31 and the second contact electrode 33 mayform ohmic contact with the first conductive type semiconductor layer 25and the second conductive type semiconductor layer 29, respectively. Thesecond contact electrode 33 is formed on an upper surface of the secondconductive type semiconductor layer 29 to cover a portion or theentirety of the second conductive type semiconductor layer 29. Thesecond contact electrode 33 is provided as a monolithic layer and isformed to cover the upper surface of the second conductive typesemiconductor layer 29 excluding the exposed region of the firstconductive type semiconductor layer 25. By the second contact electrode33 formed as the monolithic layer, electric current can be uniformlysupplied to an overall region of the light emitting structure 23,thereby improving current spreading efficiency. It should be understoodthat the second contact electrode 33 may include a plurality of unitelectrodes, as needed.

The second contact electrode 33 may be formed of any material capable offorming ohmic contact with the second conductive type semiconductorlayer 29 and may include, for example, at least one of a metallicmaterial and a conductive oxide.

In the structure wherein the second contact electrode 33 includes ametallic material, the second contact electrode 33 may include areflective layer (not shown) and a cover layer (not shown) covering thereflective layer. With this structure, light emitted from the lightemitting structure 23 can be reflected by the second contact electrode33. The reflective layer may include a metal having high reflectance andcapable of forming ohmic contact with the second conductive typesemiconductor layer 29. For example, the reflective layer may include atleast one of Ni, Pt, PD, Rh, W, Ti, Al, Ma, Ag or Au, and may becomposed of a single layer or multiple layers.

The cover layer can prevent inter-diffusion of materials between thereflective layer and other layers, and can prevent external materialsfrom diffusing into and damaging the reflective layer. With thereflective layer contacting the second conductive type semiconductorlayer 29, the cover layer may be formed to cover an upper surface and aside surface of the reflective layer. In the structure wherein the coverlayer covers the side surface of the reflective layer, the cover layerand the second conductive type semiconductor layer 29 are electricallyconnected to each other such that the cover layer and the reflectivelayer can be used as contact electrodes. The cover layer may include atleast one of, for example, Au, Ni, Ti or Cr, and may be composed of asingle layer or multiple layers.

Each of the reflective layer and the cover layer may be formed by e-beamevaporation or plating.

In the structure wherein the second contact electrode 33 includes aconductive oxide, the conductive oxide may include ITO, ZnO, AZO, orIZO, and the like. The second contact electrode 33 including theconductive oxide may be formed to cover a larger area of the secondconductive type semiconductor layer 29 than the second contact electrodeincluding a metal. The structure wherein the second contact electrode 33includes a conductive oxide has a shorter separation distance from theperiphery of the exposed region of the first conductive typesemiconductor layer 25 to the second contact electrode 33 than thestructure wherein the second contact electrode 33 includes a metal. As aresult, the shortest distance from a contact portion between the secondcontact electrode 33 and the second conductive type semiconductor layer29 to a contact portion between the first contact electrode 31 and thefirst conductive type semiconductor layer 25 is relatively reduced,whereby the forward voltage Vf of the light emitting element 10 can bereduced.

The difference in the area of the second contact electrode 33 betweenthe structure wherein the second contact electrode 33 includes themetallic material and the structure wherein the second contact electrode33 includes the conductive oxide can be caused by a difference infabrication method. For example, in use of the metallic material, sincethe second contact electrode 33 is formed by deposition or plating, aseparation between outer peripheries of the second contact electrode 33and the second conductive type semiconductor layer 29 is formed due toprocess margin of a mask. Conversely, the conductive oxide is formedover the entire region of the second conductive type semiconductor layer29 and is then removed together with the second conductive typesemiconductor layer 29 during etching to expose the first conductivetype semiconductor layer 25. As a result, the conductive oxide can beformed closer to the outer periphery of the second conductive typesemiconductor layer 29.

The first insulation layer 35 may be formed to partially cover an uppersurface of the light emitting structure 23 and the second contactelectrode 33. Further, the first insulation layer 35 may be formed tocover side surfaces of the holes h such that the first conductive typesemiconductor layer 25 can be partially exposed through bottom surfacesof the holes h. Further, the first insulation layer 35 may be formedwith at least one opening through which a portion of the second contactelectrode 33 is exposed.

The first insulation layer 35 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The first insulationlayer 35 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked.

In the structure wherein the second contact electrode 33 includes theconductive oxide, the first insulation layer 35 may include adistributed Bragg reflector to improve luminous efficacy of the lightemitting element 10. Further, in the structure wherein the secondcontact electrode 33 includes the conductive oxide, the first insulationlayer 35 is formed using a transparent insulation oxide (for example,SiO₂) to form an omnidirectional reflector by a stack structure of thesecond contact electrode 33, the first insulation layer 35 and the firstcontact electrode 31.

The first contact electrode 31 may be formed to cover the entirety ofthe first insulation layer 35 excluding a portion thereof in which theopening partially exposing the second contact electrode 33 is formed. Asa result, the first insulation layer 35 may be partially interposedbetween the first contact electrode 31 and the second contact electrode33.

Although not shown in FIGS. 2A and 2B, the first insulation layer 35 mayalso be formed to cover a portion of a side surface of the lightemitting structure 23. This structure of the first insulation layer 35can vary depending upon chip unit isolation in fabrication of the lightemitting element 10. When the first insulation layer 35 is formed afterchip unit isolation of a wafer in fabrication of the light emittingelement 10, the side surface of the light emitting structure 23 can alsobe covered by the first insulation layer 35.

The first contact electrode 31 is formed to partially cover the lightemitting structure 23. The first contact electrode 31 is formed to fillthe holes h, thereby forming ohmic contact with the first conductivetype semiconductor layer 25 not covered by the first insulation layer 35placed corresponding to the holes h. In the first exemplary embodiment,the first contact electrode 31 may be formed to cover the entirety ofthe first insulation layer 35 excluding a portion of the firstinsulation layer 35. With this structure, light emitted from the lightemitting structure 23 can be reflected by the first contact electrode31, and a first contact layer and a second contact layer can beelectrically insulated from each other by the first insulation layer 35.

The first contact electrode 31 is formed to cover the entire uppersurface of the light emitting structure 23 excluding some regions,thereby further improving current spreading efficiency of the lightemitting element. Further, the first contact electrode 31 may also covera portion of the light emitting structure not covered by the secondcontact electrode 33, thereby improving luminous efficacy of the lightemitting element 10 through more effective reflection of light.

The first contact electrode 31 serves to form ohmic contact with thefirst conductive type semiconductor layer 25 while reflecting light.Thus, the first contact electrode 31 may include a highly reflectivemetal layer such as an Al layer and may be composed of a single layer ormultiple layers. Here, the highly reflective metal layer may be formedon a contact layer such as a Ti, Cr or Ni layer, and the first contactelectrode 31 may include at least one of Ni, Pt, Pd, Rh, W, Ti, Al, Mg,Ag, or Au.

As in the first insulation layer 35, the first contact electrode 31 maybe formed to cover a portion of the side surface of the light emittingstructure 23. In the structure wherein the first contact electrode 31 isalso formed on the side surface of the light emitting structure 23, thefirst contact electrode 31 reflects light emitted from the active layer27 to the side surface of the light emitting structure, therebyimproving luminous efficacy of the light emitting element 10. In thestructure wherein the first contact electrode 31 is formed to cover aportion of the side surface of the light emitting structure 23, thefirst insulation layer 35 may be interposed between the light emittingstructure 23 and the first contact electrode 31.

The second insulation layer 37 is formed to cover the entire region ofthe first contact electrode 31 excluding some regions thereof. Thesecond insulation layer 37 may be formed with a first opening op1 thatpartially exposes the first contact electrode 31 and a second openingop2 that partially exposes the second contact electrode 33. Here, thesecond insulation layer 37 may include one or more first openings op1and one or more second openings op2.

The second insulation layer 37 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The second insulationlayer 37 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked. In the structure wherein thesecond insulation layer 37 is composed of multiple layers, an uppermostlayer of the second insulation layer 37 is formed of or includesSiN_(x). The structure wherein the uppermost layer of the secondinsulation layer 37 is formed of or includes SiN_(x) can moreeffectively prevent moisture penetration into the light emittingstructure 23.

The first electrode pad 39 and the second electrode pad 41 may bedisposed on the light emitting structure 23 and electrically connectedto the first contact electrode 31 and the second contact electrode 33,respectively. The first electrode pad 39 directly contacts the firstcontact electrode 31 to be electrically connected thereto through thefirst openings op1, and the second electrode pad 41 directly contactsthe second contact electrode 33 to be electrically connected theretothrough the second openings op2.

Each of the first electrode pad 39 and the second electrode pad 41 has athickness of dozens of micrometers, whereby the light emitting element10 can be used as a chip-scale package.

Each of the first electrode pad 39 and the second electrode pad 41 maybe composed of a single layer or multiple layers and may include anelectrically conductive material. For example, each of the firstelectrode pad 39 and the second electrode pad 41 may include at leastone of Cu, Pt, Au, Ti, Ni, Al or Ag, or may also include sintered metalparticles and non-metallic materials interposed between metal particles.Here, the first electrode pad 39 and the second electrode pad 41 may beformed by plating, deposition, dotting, or screen-printing, and thelike.

When the first electrode pad 39 and the second electrode pad 41 areformed by plating, a seed metal layer is formed over the first openingsop1 and the second openings op2 by sputtering. The seed metal layer mayinclude Ti, Cu, Au, or Cr, and the like, and can serve as an under bumpmetallization layer (UBM layer). For example, the seed metal layer mayhave a Ti/Cu stack structure. After the seed metal layer is formed, amask is formed on the seed metal layer so as to cover a portioncorresponding to a region, in which an insulation support will beformed, while opening regions in which the first and second electrodepads 39, 41 will be formed. Then, the first and second electrode pads39, 41 are formed in the open regions of the mask through plating,followed by etching to remove the mask and the seed metal layer, therebyforming the first and second electrode pads 39, 41.

The following description will be given of forming the first and secondelectrode pads 39, 41 by screen-printing. The UBM layer is formed on atleast some of the first openings op1 and the second openings op2 throughdeposition such as sputtering and patterning, or through deposition andlift-off. The UBM layer may be formed in regions in which the first andsecond electrode pads 39, 41 will be formed, and may include a Ti or TiWlayer and a Cu, Ni, or Au or combination layer. For example, the UBMlayer may have a Ti/Cu stack structure. Then, a mask is formed on theUBM layer so as to cover a portion corresponding to a region, in whichan insulation support will be formed, while opening regions in which thefirst and second electrode pads 39, 41 will be formed. Thereafter, amaterial such as Ag pastes, Au pastes, or Cu pastes is printed in theopen regions by screen-printing and is cured. Thereafter, the mask isremoved by etching, thereby forming the first and second electrode pads39, 41.

When the first and second electrode pads 39, 41 are formed by themethods as described above, the first and second electrode pads 39, 41may be formed at corners of the light emitting structure 23,respectively, as shown in FIG. 1, in the first exemplary embodiment.Further, the sizes of the first electrode pad 39 and the secondelectrode pad 41 may be adjusted to form a space between the first andsecond electrode pads 39, 41. The sizes of the first electrode pad 39and the second electrode pad 41 may be determined to have apredetermined area or less at the corners of the light emittingstructure 23.

In the first exemplary embodiment, each of the first electrode pad 39and the second electrode pad 41 may be formed in a triangular shape atthe corresponding corner of the light emitting structure 23 and the heatdissipation pad 43 may be formed in a hexagonal shape between the firstelectrode pad 39 and the second electrode pad 41 on the upper surface ofthe light emitting structure 23.

The heat dissipation pad 43 may be formed on the upper surface of thelight emitting structure 23 and contact the second insulation layer 37.The heat dissipation pad 43 may have the same thickness as the first andsecond electrode pads 39, 41, or may have a smaller thickness than thefirst and second electrode pads 39, 41. Further, the heat dissipationpad 43 may have a larger area than the first and second electrode pads39, 41 in plan view and thus at least three sides of the heatdissipation pad 43 may be exposed to the outside, as shown in FIG. 1.For example, the heat dissipation pad may be formed to have an areaoccupying 50% or more of the area of the light emitting element in planview and a large area of the heat dissipation pad can provide betterheat dissipation efficiency.

In the first exemplary embodiment, since each of the first electrode pad39 and the second electrode pad 41 is formed to have a predeterminedarea or less at the corresponding corner of the light emitting structure23, the heat dissipation pad 43 may be formed in an overall region inwhich the first and second electrode pads 39, 41 are not formed. Here,the first and second electrode pads 39, 41 may be separated from theheat dissipation pad 43 by a predetermined distance or more. In someimplementations, the heat dissipation pad 43 may be formed of or includethe same material as the first and second electrode pads 39, 41, and theheat dissipation pad 43 may be separated from the first and secondelectrode pads 39, 41 to prevent electric current from flowing to theheat dissipation pad 43. Here, the shapes of the first and secondelectrode pads 39, 41 and the shape of the heat dissipation pad 43 arenot limited to the shapes shown in the drawings, and may be changed invarious ways, as needed.

FIGS. 3A and 3B are views illustrating a junction temperature dependingupon the area of the heat dissipation pad 43 of the light emittingelement 10 according to the first exemplary embodiment of the presentdisclosure.

FIG. 3A is a bottom view of a typical light emitting element and FIG. 3Bis a bottom view of the light emitting element according to the firstexemplary embodiment of the present disclosure, in which the lightemitting element 10 includes the first electrode pad 39, the secondelectrode pad 41 and the heat dissipation pad 43. The typical lightemitting element includes first and second electrode pads withoutincluding the heat dissipation pad 43, and the light emitting elementaccording to the first exemplary embodiment includes the heatdissipation pad and the first and second electrode pads 39, 41, in whicheach side of each of the first and second electrode pads 39, 41 has alength of about 500 μm.

For comparison of the light emitting element according to the firstexemplary embodiment with the typical light emitting element, currentdensity and the maximum applicable current were measured, and it couldbe confirmed that the junction temperature of the light emitting elementaccording to the first exemplary embodiment was decreased due toformation of the heat dissipation pad. With this structure, the lightemitting element according to the first exemplary embodiment couldsecure stable reliability upon high current driving within apredetermined operation range.

FIG. 4 is a bottom view of a light emitting element according to asecond exemplary embodiment of the present disclosure and FIG. 5 is across-sectional view taken along line C-C′ of FIG. 4.

The light emitting element 10 according to the second exemplaryembodiment of the present disclosure includes a light emitting structure23, a first contact electrode 31, a second contact electrode 33, a firstinsulation layer 35, a second insulation layer 37, a first electrode pad39, a second electrode pad 41, and a heat dissipation pad 43. Indescription of the light emitting element 10 according to the secondexemplary embodiment, descriptions of the same components as those ofthe first exemplary embodiment will be omitted.

Referring to FIG. 4 and FIG. 5, the light emitting element 10 accordingto the second exemplary embodiment includes a plurality of lightemitting structures 23 a, 23 b connected to each other in series. Foreasy understanding of this exemplary embodiment, the followingdescription will focus on series connection between a first lightemitting structure 23 a and a second light emitting structure 23 b. Thefirst light emitting structure 23 a and the second light emittingstructure 23 b are formed on a substrate 21 to be separated from eachother, and the first insulation layer 35 and the first contact electrode31 are formed in a space between the first light emitting structure 23 aand the second light emitting structure 23 b. The first and second lightemitting structures 23 a, 23 b according to this exemplary embodimentare the same structure as those of the first exemplary embodiment.

With the plurality of light emitting structures 23 a, 23 b connected toeach other in series, the second insulation layer 37 is formed to coverall of the light emitting structures 23 a, 23 b, and the first electrodepad 39, the second electrode pad 41 and the heat dissipation pad 43 areformed on the second insulation layer 37. Here, the first electrode pad39 electrically contacts the first contact electrode 31 through thefirst openings op1 and the second electrode pad 41 electrically contactsthe second contact electrode 33 through the second openings op2. Theheat dissipation pad 43 is separated from the first and second electrodepads 39, 41 and is formed on the second insulation layer 37.

Although the plurality of light emitting structures 23 a, 23 b areillustrated as being connected to each other in series in the secondexemplary embodiment, the plurality of light emitting structures 23 a,23 b may be connected to each other in parallel or in series-parallel.

FIG. 6 is a bottom view of a light emitting element according to a thirdexemplary embodiment of the present disclosure.

Referring to FIG. 6, the light emitting element 10 according to thethird exemplary embodiment of the present disclosure includes a lightemitting structure 23, a first contact electrode 31, a second contactelectrode 33, a first insulation layer 35, a second insulation layer 37,first electrode pads 391, 39 b, second electrode pads 41 a, 41 b, and aheat dissipation pad 43. In description of the light emitting element 10according to the third exemplary embodiment, descriptions of the samecomponents as those of the first exemplary embodiment will be omitted.

In the third exemplary embodiment, the light emitting element 10includes a pair of first electrode pads 39 a, 39 b and a pair of secondelectrode pads 41 a, 41 b, in which each of the first and secondelectrode pads 39 a, 39 b, 41 a, 41 b is formed in a triangular shape ata corner of the light emitting structure 23. The heat dissipation pad 43may be formed in an octagonal shape between the first and secondelectrode pads 39 a, 39 b, 41 a, 41 b. In this structure, four sides ofthe heat dissipation pad 43 having an octagonal shape are adjacent tothe first and second electrode pads 39 a, 39 b, 41 a, 41 b, and theremaining four sides thereof are exposed to an outer surface of thelight emitting structure 23.

FIG. 7 is a bottom view of a light emitting element according to afourth exemplary embodiment of the present disclosure.

Referring to FIG. 7, the light emitting element 10 according to thefourth exemplary embodiment includes a light emitting structure 23, afirst contact electrode 31, a second contact electrode 33, a firstinsulation layer 35, a second insulation layer 37, a first electrode pad39, a second electrode pad 41, and heat dissipation pads 43 a, 43 b, 43c, 43 d. In description of the light emitting element 10 according tothe fourth exemplary embodiment, descriptions of the same components asthose of the first exemplary embodiment will be omitted.

In the fourth exemplary embodiment, each of the first electrode pad 39and the second electrode pad 41 has a triangular shape and is disposedin a diagonal direction at a corner of the light emitting structure 23.In addition, four heat dissipation pads 43 a, 43 b, 43 c, 43 d aredisposed between the first electrode pad 39 and the second electrode pad41. Among the four heat dissipation pads 43 a, 43 b, 43 c, 43 d, twoheat dissipation pads 43 b, 43 d, disposed in regions in which the firstand second electrode pads 39, 41 are not formed, have a rectangularshape, and the remaining two heat dissipation pads 43 a, 43 c have arectangular shape having a chamfered corner. The four heat dissipationpads 43 a, 43 b, 43 c, 43 d are separated from each other and from thefirst and second electrode pads 39, 41.

FIG. 8 is a bottom view of a light emitting element according to a fifthexemplary embodiment of the present disclosure and FIG. 9 is across-sectional view taken along line A-A′ of FIG. 1.

Referring to FIG. 8 and FIG. 9, the light emitting element 10 accordingto the fifth exemplary embodiment includes first to fourth lightemitting cells C1, C2, C3, C4, a first electrode pad 39, and a secondelectrode pad 41.

Although four light emitting cells C1, C2, C3, C4 are used in the fifthexemplary embodiment as shown in FIG. 8, it should be understood thatthe light emitting element 10 may include more or fewer than four lightemitting cells, as needed.

The first to fourth light emitting cells C1, C2, C3, C4 are connected toeach other in series, and among the first to fourth light emitting cellsC1, C2, C3, C4, the third light emitting cell C3 is disposed at thecenter of the light emitting element 10 and the remaining light emittingcells C1, C2, C4 are disposed to surround the third light emitting cellC3. Here, the first to fourth light emitting cells C1, C2, C3, C4 areconnected to each other in series such that electric current appliedthrough the first and second electrode pads 39, 41 sequentially flowsfrom the first light emitting cell C1 to the fourth light emitting cellC4.

In this exemplary embodiment, the light emitting element 10 has arectangular shape and the third light emitting cell C3 has a circularshape in plan view. However, it should be understood that the shapes ofthe light emitting element 10 and the third light emitting cell C3 maybe changed in various ways, for example, including a triangular shape, arectangular shape, a hexagonal shape, or an octagonal shape, and thelike, as needed.

With the third light emitting cell C3 having a circular shape disposedat the center of the light emitting element 10 having a rectangularshape, the first light emitting cell C1, the second light emitting cellC2 and the fourth light emitting cell C4 are formed to have differentshapes such that the light emitting element 10 has a rectangular shape.

The first light emitting cell C1 is disposed at an upper right side ofthe third light emitting cell C3 and the second light emitting cell C2is disposed at an upper left side of the third light emitting cell C3.The fourth light emitting cell C4 is disposed below the third lightemitting cell C3. In this structure, the first light emitting cell C1and the second light emitting cell C2 may be arranged in linearsymmetry.

As described above, the first light emitting cell C1 is electricallyconnected to the second light emitting cell C2, the second lightemitting cell C2 is electrically connected to the third light emittingcell C3, and the third light emitting cell C3 is electrically connectedto the fourth light emitting cell C4 such that electric current cansequentially flow from the first light emitting cell C1 to the fourthlight emitting cell C4. To this end, the first light emitting cell C1 iselectrically connected to the second light emitting cell C2 above thethird light emitting cell C3, and is separated from the third lightemitting cell C3 and the fourth light emitting cell C4 by apredetermined distance or more so as to be electrically insulatedtherefrom.

In addition, the second light emitting cell C2 is electrically connectedto the first light emitting cell C1 above the third light emitting cellC3, and is electrically connected to the third light emitting cell C3 atthe upper left side of the third light emitting cell C3. The secondlight emitting cell C2 is separated from the fourth light emitting cellC4 by a predetermined distance or more so as to be electricallyinsulated therefrom.

The third light emitting cell C3 is electrically connected to the secondlight emitting cell C2, and is electrically connected to the fourthlight emitting cell C4 below the third light emitting cell C3. The thirdlight emitting cell C3 is separated from the first light emitting cellC1 by a predetermined distance or more so as to be electricallyinsulated therefrom.

The fourth light emitting cell C4 is electrically connected to the thirdlight emitting cell C3 and is separated from the first and second lightemitting cells C1, C2 by a predetermined distance or more so as to beelectrically insulated therefrom.

The first to fourth light emitting cells C1, C2, C3, C4 may have thesame size. Since the first to fourth light emitting cells C1, C2, C3, C4are connected to each other in series, light can be uniformly emittedfrom each of the first to fourth light emitting cells C1, C2, C3, C4having the same area.

Although the first to fourth light emitting cells C1, C2, C3, C4 areillustrated as being connected to one another in series in the fifthexemplary embodiment, the first to fourth light emitting cells C1, C2,C3, C4 may be connected to one another in parallel or inseries-parallel.

With the first to fourth light emitting cells C1, C2, C3, C4 disposed onthe light emitting element as described above, the first and secondelectrode pads 39, 41 are disposed on the first to fourth light emittingcells C1, C2, C3, C4. In addition, the first electrode pad 39 iselectrically connected to the fourth light emitting cell C4 and thesecond electrode pad 41 is electrically connected to the first lightemitting cell C1. That is, the first electrode pad 39 is notelectrically connected to the first to third light emitting cells C1,C2, C3, and the second electrode pad 41 is not electrically connected tothe second to fourth light emitting cells C2, C3, C4.

The first and second electrode pads 39, 41 may be disposed at oppositeends of the light emitting element 10 and the sizes of the first andsecond electrode pads 39, 41 may be adjusted so as to form a spacehaving a predetermined distance or more between the first electrode pad39 and the second electrode pad 41.

Referring to FIG. 9, the light emitting element 10 according to thefifth exemplary embodiment will be described in more detail. The lightemitting element 10 according to the fifth exemplary embodiment furtherincludes a light emitting structure 23, a first contact electrode 31, asecond contact electrode 33, a first insulation layer 35, and a secondinsulation layer 37.

In description of the light emitting element 10 according to the fifthexemplary embodiment, descriptions of components that are the same asthose of the first exemplary embodiment will be omitted.

The light emitting structure 23 includes a first conductive typesemiconductor layer 25, an active layer 27 disposed on the firstconductive type semiconductor layer 25, and a second conductive typesemiconductor layer 29 disposed on the active layer 27.

The light emitting structure 23 may include a partially exposed regionof the first conductive type semiconductor layer 25 formed by partiallyremoving the second conductive type semiconductor layer 29 and theactive layer 27. That is, as shown in FIG. 9, a plurality of holes h maybe formed through the second conductive type semiconductor layer 29 andthe active layer 27 to expose the first conductive type semiconductorlayer 25. Here, the shape and arrangement of the holes h may be modifiedin various ways. In the partially exposed region of the first conductivetype semiconductor layer 25, a mesa including the second conductive typesemiconductor layer 29 and the active layer 27 may be formed bypartially removing the second conductive type semiconductor layer 29 andthe active layer 27.

A growth substrate may be disposed under the first conductive typesemiconductor layer 25 of the light emitting structure 23.

The first contact electrode 31 and the second contact electrode 33 mayform ohmic contact with the first and second conductive typesemiconductor layers 25, 29, respectively. The second contact electrode33 is formed on an upper surface of the second conductive typesemiconductor layer 29 to cover a portion or the entirety of the secondconductive type semiconductor layer 29.

The first insulation layer 35 may be formed to partially cover an uppersurface of the light emitting structure 23 and the second contactelectrode 33. Further, the first insulation layer 35 may be formed tocover side surfaces of the holes h such that the first conductive typesemiconductor layer 25 can be partially exposed through bottom surfacesof the holes h. Further, the first insulation layer 35 may be formedwith at least one opening through which a portion of the second contactelectrode 33 is exposed.

The first contact electrode 31 may be formed to cover the entirety ofthe first insulation layer 35 excluding a portion thereof in which theopening partially exposing the second contact electrode 33 is formed. Asa result, the first insulation layer 35 may be partially interposedbetween the first contact electrode 31 and the second contact electrode33.

The first insulation layer 35 may also be formed to partially cover aside surface of the light emitting structure 23.

The first contact electrode 31 is formed to partially cover the lightemitting structure 23. The first contact electrode 31 is formed to fillthe holes h, thereby forming ohmic contact with the first conductivetype semiconductor layer 25 not covered by the first insulation layer 35placed corresponding to the holes h. In the first exemplary embodiment,the first contact electrode 31 may be formed to cover the entirety ofthe first insulation layer 35 excluding a portion of the firstinsulation layer 35. With this structure, light emitted from the lightemitting structure 23 can be reflected by the first contact electrode31, and a first contact layer and a second contact layer can beelectrically insulated from each other by the first insulation layer 35.

The second insulation layer 37 is formed to cover the entire region ofthe first contact electrode 31 excluding some regions thereof. Thesecond insulation layer 37 may be formed with a first opening op1 thatpartially exposes the first contact electrode 31 and a second openingop2 that partially exposes the second contact electrode 33. Here, thesecond insulation layer 37 may include one or more first openings op1and one or more second openings op2.

The first electrode pad 39 and the second electrode pad 41 may bedisposed on the light emitting structure 23 and electrically connectedto the first contact electrode 31 and the second contact electrode 33,respectively. The first electrode pad 39 directly contacts with thefirst contact electrode 31 to be electrically connected thereto throughthe first openings op1, and the second electrode pad 41 directlycontacts with the second contact electrode 33 to be electricallyconnected thereto through the second openings op2.

In the fifth exemplary embodiment, since the first electrode pad 39 iselectrically connected to the fourth light emitting cell C4, the firstopenings may be formed in the fourth light emitting cell C4. Thus, asshown in FIG. 9, the first electrode pad 39 is disposed on the secondinsulation layer 37 without being electrically connected to the secondlight emitting cell C2.

Further, in order to achieve series connection between the first lightemitting cell C1 and the second light emitting cell C2, the firstcontact electrode 31 of the first light emitting cell C1 electricallycontacts with the second contact electrode 33 of the second lightemitting cell C2. Here, the first contact electrode 31 of the firstlight emitting cell C1 may be formed on a space between the first lightemitting cell C1 and the second light emitting cell C2. In someimplementations, the first contact electrode 31 may fill the spacebetween the first light emitting cell C1 and the second light emittingcell C2.

Each of the first electrode pad 39 and the second electrode pad 41 has athickness of dozens of micrometers, whereby the light emitting element10 can be used as a chip-scale package.

Further, each of the first electrode pad 39 and the second electrode pad41 may be composed of a single layer or multiple layers, and may includean electrically conductive material.

FIG. 10 is a side sectional view of a light emitting diode including thelight emitting element according to the fifth exemplary embodiment ofthe present disclosure and a dome-shaped lens. FIG. 11 is a sidesectional view of a light emitting diode including the light emittingelement according to the fifth exemplary embodiment of the presentdisclosure and a total reflection type lens.

In the light emitting diode including the light emitting elementaccording to the fifth exemplary embodiment, the light emitting element10 may be mounted on a printed circuit board 1200 and a dome-shaped lens1310 may be coupled to an upper side of the light emitting element 10.The dome-shaped lens 1310 includes a light incidence plane 1312 uponwhich light emitted from the light emitting element 10 is incident, anda light exit plane 1314 defined on an upper surface of the lens 1310.The light incident plane 1312 may have a flat shape and may be changedto have various shapes, as needed. The light exit plane 1314 may have acircular cross-sectional shape or a modified circular cross-sectionalshape.

The light emitting element 10 is mounted on the printed circuit board1200 such that external power can be applied to the printed circuitboard 1200 through the first electrode pad 39 and the second electrodepad 41 of the light emitting element 10. The printed circuit board 1200may be formed at a lower side thereof with a dissipation portion thatdissipates heat transferred from the light emitting element 10.

As a result of comparing luminous efficacy of the light emitting diodeincluding the light emitting element 10 according to the fifth exemplaryembodiment and having the structure as described above with that of atypical light emitting diode having the same structure, it could be seenthat the light emitting diode according to the fifth exemplaryembodiment had a luminous efficacy of 100.7% when the typical lightemitting diode had a luminous efficacy of 100%.

In comparison of the light emitting diode according to the fifthexemplary embodiment with the typical light emitting diode, the samekind of phosphor having a color coordinate CIEx of 0.330 was used.

Furthermore, in the structure wherein a total reflection type lens 1320as shown in FIG. 11 is applied to the light emitting diode, lightemitted from the light emitting diode according to the fifth exemplaryembodiment has high brightness at the center of the light emittingdiode, thereby improving luminous efficacy of the light emitting diode.

The total reflection type lens 1320 may be a TIR lens, an upper surfaceof which has a total reflection function. Namely, the total reflectiontype lens 1320 includes a light incidence plane 1322 on which lightemitted from the light emitting element 10 is incident, a reflectionportion 1324 disposed on an upper surface thereof, and a light exitplane 1326 defined on a side surface thereof. Thus, when light emittedfrom the light emitting element 10 enters the total reflection type lens1320, the light is reflected to the side surface of the total reflectiontype lens 1320 and passes therethrough. Although the light incidenceplane 1322 is shown as having a flat shape in this exemplary embodiment,the light incidence plane 1322 may have a concave shape, as needed.

FIG. 12 is a bottom view of a light emitting element according to asixth exemplary embodiment of the present disclosure, and FIG. 13A, FIG.13B and FIG. 13C are cross-sectional views taken along lines A-A′, B-B′and C-C′ of FIG. 12, respectively.

Referring to FIG. 12 and FIGS. 13A-13C, the light emitting element 10according to the sixth exemplary embodiment includes first to fourthlight emitting cells C1, C2, C3, C4, a first electrode pad 39, a secondelectrode pad 41, and a heat dissipation pad 43.

Although four light emitting cells C1, C2, C3, C4 are used in the sixthexemplary embodiment as shown in FIG. 8, it should be understood thatthe light emitting element 10 may include more or fewer than four lightemitting cells, as needed.

The first to fourth light emitting cells C1, C2, C3, C4 are connected toeach other in series, and among the first to fourth light emitting cellsC1, C2, C3, C4, the third light emitting cell C3 is disposed at thecenter of the light emitting element 10 and the remaining light emittingcells C1, C2, C4 are disposed to surround the third light emitting cellC3. In addition, the first to fourth light emitting cells C1, C2, C3, C4are connected to one another in series such that electric currentapplied through the first and second electrode pads 39, 41 sequentiallyflows from the first light emitting cell C1 to the fourth light emittingcell C4.

Here, the light emitting element 10 has a rectangular shape and thethird light emitting cell C3 has a circular shape in plan view. However,it should be understood that the shapes of the light emitting element 10and the third light emitting cell C3 may be changed to have variousshapes, including, for example, a triangular shape, a rectangular shape,a hexagonal shape, an or octagonal shape, and the like, as needed.

With the third light emitting cell C3 of a circular shape disposed atthe center of the light emitting element 10 having a rectangular shape,the first light emitting cell C1, the second light emitting cell C2 andthe fourth light emitting cell C4 are formed to have different shapessuch that the light emitting element 10 has a rectangular shape.

In the sixth exemplary embodiment, the first to fourth light emittingcell are disposed coplanar with each other, as shown in FIG. 12. Forconvenience of description, spatially relative terms such as upper,lower, left and right will be described with reference to FIG. 12.

The first light emitting cell C1 is disposed at an upper right side ofthe third light emitting cell C3 and the second light emitting cell C2is disposed at an upper left side of the third light emitting cell C3.The fourth light emitting cell C4 is disposed below the third lightemitting cell C3. In this structure, the first light emitting cell C1and the second light emitting cell C2 may be arranged in line symmetry.

Further, the second light emitting cell C2 is electrically connected tothe first light emitting cell C1 above the third light emitting cell C3and is electrically connected to the third light emitting cell C3 at theupper left side of the third light emitting cell C3. The second lightemitting cell C2 is separated from the fourth light emitting cell C4 bya predetermined distance or more so as to be electrically insulatedtherefrom.

The fourth light emitting cell C4 is electrically connected to the thirdlight emitting cell C3 and is separated from the first and second lightemitting cells C1, C2 by a predetermined distance or more so as to beelectrically insulated therefrom.

Although the first to fourth light emitting cells C1, C2, C3, C4 areillustrated as being connected to each other in series in the sixthexemplary embodiment, the first to fourth light emitting cells C1, C2,C3, C4 may be connected to each other in parallel or in series-parallel.

With the first to fourth light emitting cells C1, C2, C3, C4 disposed onthe light emitting element as described above, the first and secondelectrode pads 39, 41 are disposed on the fourth light emitting cell C4and the first light emitting cell C1. In addition, the first electrodepad 39 is electrically connected to the fourth light emitting cell C4and the second electrode pad 41 is electrically connected to the firstlight emitting cell C1.

In this exemplary embodiment, the first and second electrode pads 39, 41may be formed in a triangular shape at the corresponding corners of thelight emitting cells C1, C2, C3, C4, and the heat dissipation pad 43 maybe formed in a hexagonal shape between the first electrode pad 39 andthe second electrode pad 41. Here, the shapes of the first and secondelectrode pads 39, 41 and the shape of the heat dissipation pad 43 arenot limited to the shapes shown in the drawings, and may be changed invarious ways, as needed. In addition, the first electrode pad 39, thesecond electrode pad 41 and the heat dissipation pad 43 may be separatedfrom one another by a predetermined distance.

As described above, in the structure wherein the third light emittingcell C3 is disposed at the center of the light emitting element 10, andthe first light emitting cell C1, the second light emitting cell C2 andthe fourth light emitting cell C4 are disposed to surround the thirdlight emitting cell C3, luminous efficacy at the center of the lightemitting element 10 can be improved by increasing current density of thethird light emitting cell C3. For example, the current density of thethird light emitting cell C3 can be increased by forming the third lightemitting cell C3 to have a smaller area than the light emitting cellsC1, C2, C4.

When the current density of the third light emitting cell C3 isincreased, heat can be intensively generated from the third lightemitting cell C3. Thus, in order to dissipate heat from the third lightemitting cell C3, the heat dissipation pad 43 is provided to the lightemitting element, and in the sixth exemplary embodiment, the heatdissipation pad 43 may be disposed to cover the entirety of the thirdlight emitting cell C3, as shown in FIG. 12.

Referring to FIGS. 13A-13C, the light emitting element 10 according tothe sixth exemplary embodiment will be described in more detail. Thelight emitting element 10 according to the sixth exemplary embodimentmay further include a substrate 21, a light emitting structure 23, afirst contact electrode 31, a second contact electrode 33, a firstinsulation layer 35, and a second insulation layer 37.

The substrate 21 may be any substrate which allows growth of the lightemitting structure 23 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, or an aluminum nitride substrate. The substrate 21may be removed from the light emitting structure 23 using a techniqueknown in the art, as needed. Although not shown in the drawings, thelight emitting structure 23 may have a rough region formed on a lowersurface thereof.

The light emitting structure 23 includes a first conductive typesemiconductor layer 25, an active layer 27 disposed on the firstconductive type semiconductor layer 25, and a second conductive typesemiconductor layer 29 disposed on the active layer 27.

The light emitting structure 23 may include a partially exposed regionof the first conductive type semiconductor layer 25 formed by partiallyremoving the second conductive type semiconductor layer 29 and theactive layer 27. That is, as shown in FIGS. 13A-13C, a plurality ofholes h may be formed through the second conductive type semiconductorlayer 29 and the active layer 27 to expose the first conductive typesemiconductor layer 25. Here, the shape and arrangement of the holes hmay be modified in various ways.

The first contact electrode 31 and the second contact electrode 33 mayform ohmic contact with the first conductive type semiconductor layer 25and the second conductive type semiconductor layer 29, respectively. Thesecond contact electrode 33 may be formed on an upper surface of thesecond conductive type semiconductor layer 29 to cover a portion or theentirety of the second conductive type semiconductor layer 29.

The second contact electrode 33 may be formed of any material capable offorming ohmic contact with the second conductive type semiconductorlayer 29 and may include, for example, at least one of a metallicmaterial and a conductive oxide.

The first insulation layer 35 may be formed on the upper surface of thelight emitting structure 23 to cover the entirety of the light emittingstructure 23 excluding some regions thereof through which the secondcontact electrode 33 is exposed. Further, the first insulation layer 35is formed to cover the second conductive type semiconductor layer 29 andthe active layer 28 exposed through the holes h formed in the lightemitting structure 23. The first insulation layer may be formed onbottom surfaces of the holes h such that the first conductive typesemiconductor layer 25 is partially exposed through bottom surfaces ofthe holes h so as to allow ohmic contact between the first conductivetype semiconductor layer 25 and the first contact electrode 31. Thefirst insulation layer 35 may be formed on the second contact electrode33 such that the second contact electrode 33 can be partially exposed.

The first insulation layer 35 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The first insulationlayer 35 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked.

Although not shown in FIGS. 14A-14C, the first insulation layer 35 mayalso be formed to cover a portion of the substrate 21. This structure ofthe first insulation layer 35 can vary depending upon chip unitisolation in fabrication of the light emitting element 10. When thefirst insulation layer 35 is formed after chip unit isolation of a waferin fabrication of the light emitting element 10, a portion of thesubstrate 21 can also be covered by the first insulation layer 35.

The first contact electrode 31 may be formed on the upper surface of thelight emitting structure 23 so as to cover the entirety of the firstinsulation layer 35 excluding a portion of the first insulation layer35. Here, the first contact electrode 31 is formed to fill the holes hformed in the light emitting structure 23, thereby forming ohmic contactwith the first conductive type semiconductor layer 25 exposed throughthe bottom surfaces of the holes h. As described above, since the firstcontact electrode 31 covers most of the first insulation layer 35, lightemitted from the light emitting structure 23 can be reflected by thefirst contact electrode 31.

The first contact electrode 31 may be electrically insulated from thesecond contact electrode 33 by the first insulation layer 35.

The second insulation layer 37 is formed to cover the entire region ofthe first contact electrode 31 excluding some regions thereof. Thesecond insulation layer 37 may be formed with a first opening op1 thatpartially exposes the first contact electrode 31, as shown in FIG. 13C,and a second opening op2 that partially exposes the second contactelectrode 33, as shown in FIG. 13A. The second opening op2 may be formedthrough the first insulation layer 35, the first contact electrode 31and the second insulation layer 37. Here, the second insulation layer 37may include one or more first openings op1 and one or more secondopenings op2.

The first electrode pad 39 and the second electrode pad 41 may bedisposed on the second insulation layer 37 and electrically connected tothe first contact electrode 31 and the second contact electrode 33,respectively. The first electrode pad 39 contacts the first contactelectrode 31 to be electrically connected thereto through the firstopenings op1, and the second electrode pad 41 contacts the secondcontact electrode 33 to be electrically connected thereto through thesecond openings op2.

In the sixth exemplary embodiment, since the first electrode pad 39 iselectrically connected to the fourth light emitting cell C4, as shown inFIG. 13C, the first openings op1 may be formed in the fourth lightemitting cell C4.

In addition, as shown in FIG. 13B, the first light emitting cell C1 andthe second light emitting cell C2 may be formed on the same substrate 21and a separation space is formed between the first light emitting cellC1 and the second light emitting cell C2. Here, a side surface and abottom surface of the separation space between the first light emittingcell C1 and the second light emitting cell C2 may be covered by thefirst insulation layer 35 of the first light emitting cell C1.

In order to achieve series connection between the first light emittingcell C1 and the second light emitting cell C2, the first contactelectrode 31 of the first light emitting cell C1 electrically contactsthe second contact electrode 33 of the second light emitting cell C2.Here, the first contact electrode 31 of the first light emitting cell C1may be formed in the space between the first light emitting cell C1 andthe second light emitting cell C2 or fill the space between the firstlight emitting cell C1 and the second light emitting cell C2.

Each of the first electrode pad 39 and the second electrode pad 41 has athickness of dozens of micrometers, whereby the light emitting element10 can be used as a chip-scale package.

The heat dissipation pad 43 may be formed on an upper surface of thesecond insulation layer 37 to contact the second insulation layer 37.The heat dissipation pad 43 may have the same thickness as the first andsecond electrode pads 39, 41, or may have a smaller thickness than thefirst and second electrode pads 39, 41. Further, the heat dissipationpad 43 may have a larger area than the first and second electrode pads39, 41 in plan view and thus at least three sides of the heatdissipation pad 43 may be exposed to the outside, as shown in FIG. 12.For example, the heat dissipation pad may be formed to have an areaoccupying 50% or more the area of the light emitting element in planview and a large area of the heat dissipation pad can provide betterheat dissipation efficiency.

In the sixth exemplary embodiment, since each of the first electrode pad39 and the second electrode pad 41 is formed to have a predeterminedarea or less at the corresponding corner of the light emitting structure23, the heat dissipation pad 43 may be formed in an overall region inwhich the first and second electrode pads 39, 41 are not formed. Here,the first and second electrode pads 39, 41 may be separated from theheat dissipation pad 43 by a predetermined distance or more so as tosecure electrical insulation therebetween. That is, the heat dissipationpad 43 may be formed of the same material as the first and secondelectrode pads 39, 41, and the heat dissipation pad 43 may be separatedfrom the first and second electrode pads 39, 41 to prevent electriccurrent from flowing to the heat dissipation pad 43. Here, the shapes ofthe first and second electrode pads 39, 41 and the shape of the heatdissipation pad 43 are not limited to the shapes shown in the drawings,and may be changed in various ways, as needed.

FIG. 14A is a side sectional view of one example of coupling between thelight emitting element according to the sixth exemplary embodiment and aprinted circuit board.

In this example, a light emitting diode includes a light emittingelement 10 and a printed circuit board 1200. The light emitting element10 is the same as the light emitting element described above, and theprinted circuit board 1200 includes a substrate body 1201, an insulationportion 1203, and a lead portion 1205.

In this example, the substrate body 1201 is formed of or includes ametal and directly contacts the heat dissipation pad 43 such that heatgenerated from the light emitting element 10 is transferred to thesubstrate body 1201 through the heat dissipation pad 43. As shown in thedrawings, the printed circuit board 1200 includes at least two leadportions 1205, which are brought into contact with and electricallyconnected to the first and second electrode pads 39, 41 upon mounting ofthe light emitting element 10 on the printed circuit board 1200. Theinsulation portion 1203 is interposed between the substrate body 1201and the lead portions 1205 to insulate the lead portions 1205 from thesubstrate body 1201.

The substrate body 1201 has a protrusion in a region thereof, in whichthe lead portions 1205 are not formed, so as to contact the heatdissipation pad 43, and the height of the protrusion is the same as theheight of the lead portions 1205. Further, in order to secure electricalinsulation between the substrate body 1201 and the lead portion 1205,the protrusion of the substrate body 1201 may be separated from the leadportions 1205 by a predetermined distance or more.

FIG. 14B is a side sectional view of another example of coupling betweenthe light emitting element according to the sixth exemplary embodimentand a printed circuit board.

In this example, the light emitting diode includes the light emittingelement 10 and a printed circuit board 1200, and descriptions of thesame components as those of the above example will be omitted.

In this example, the substrate body 1201 has a protrusion in a region inwhich the lead portions 1205 are not formed, and the height of theprotrusion is the same as the height of the insulation portion 1203.Further, in order to secure electrical insulation between the substratebody 1201 and the lead portion 1205, the protrusion of the substratebody 1201 may be separated from the lead portions 1205 by apredetermined distance or more.

Further, the printed circuit board 1200 includes a dissipation portion1207 formed on the protrusion of the substrate body 1201. As shown inthe drawings, the dissipation portion 1207 is separated from the leadportions 1205 by a predetermined distance or more and has the sameheight as the lead portions 1205. Thus, when the light emitting element10 is mounted on the printed circuit board 1200, the dissipation portion1207 contacts the heat dissipation pad 43. Further, the dissipationportion 1207 may be formed of or include the same material as the leadportion 1205, but is not limited thereto.

FIG. 14C is a side sectional view of a further example of couplingbetween the light emitting element according to the sixth exemplaryembodiment and a printed circuit board.

In this example, the light emitting diode includes the light emittingelement 10 and a printed circuit board 1200, and descriptions of thesame components as those of the above example will be omitted.

In this example, the substrate body 1201 may be formed of or include aninsulation material such as silicone or ceramics, and may include leadportions 1205 formed through the substrate body 1201 from an uppersurface thereof to a lower surface thereof. The substrate body mayfurther include dissipation portions 1207 formed on the upper and lowersurfaces thereof. Thus, when the light emitting element 10 is mounted onthe printed circuit board 1200, the first and second electrode pads 39,41 directly contact the lead portions 1205, and the heat dissipation pad43 may directly contact the dissipation portions 1207. The lead portions1205 may be separated from the dissipation portions 1207.

FIG. 15 is a side sectional view of a light emitting diode including thelight emitting element according to the sixth exemplary embodiment ofthe present disclosure and a dome-shaped lens.

In the light emitting diode including the light emitting element 10according to the sixth exemplary embodiment, the light emitting element10 may be mounted on a printed circuit board 1200 and a dome-shaped lens1310 may be coupled to an upper side of the light emitting element 10.The dome-shaped lens 1310 includes a light incidence plane 1312 on whichlight emitted from the light emitting element 10 is incident, and alight exit plane 1314 defined on an upper surface of the lens 1310. Thelight incident plane 1312 may have a flat shape and may be changed tohave various shapes, as needed. The light exit plane 1314 may have acircular cross-sectional shape or a modified circular cross-sectionalshape.

The light emitting element 10 is mounted on the printed circuit board1200 such that external power can be applied to the printed circuitboard 1200 through the first electrode pad 39 and the second electrodepad 41 of the light emitting element 10. The printed circuit board 1200may be formed at a lower side thereof with a dissipation portion thatdissipates heats transferred from the light emitting element 10.

As a result of comparing luminous efficacy of the light emitting diodeincluding the light emitting element 10 according to the sixth exemplaryembodiment and having the structure as described above with that of atypical light emitting diode having the same structure, it could be seenthat the light emitting diode according to the sixth exemplaryembodiment had a luminous efficacy of 100.7% when the typical lightemitting diode had a luminous efficacy of 100%.

In comparison of the light emitting diode according to the fifthexemplary embodiment with the typical light emitting diode, the samekind of phosphor having a color coordinate CIEx of 0.330 was used.

FIG. 16 is a side sectional view of a light emitting diode including thelight emitting element according to the sixth exemplary embodiment ofthe present disclosure and a concave lens.

In the structure wherein a total reflection type lens 1320 as shown inFIG. 16 is applied to the light emitting diode, light emitted from thelight emitting diode according to the sixth exemplary embodiment hashigh brightness at the center of the light emitting diode, therebyimproving luminous efficacy of the light emitting diode.

The concave lens 1320 may be or include a TIR lens. Namely, the concavelens 1320 includes a light incidence plane 1322 on which light emittedfrom the light emitting element 10 is incident, a reflection portion1324 disposed on an upper surface thereof, and a light exit plane 1326defined on a side surface thereof. Thus, when light emitted from thelight emitting element 10 enters the concave lens 1320, the light isreflected to the side surface of the concave lens 1320 and is emittedtherethrough. Although the light incidence plane 1322 is shown as havinga flat shape in this exemplary embodiment, the light incidence plane1322 may have a convex shape, as needed.

FIGS. 17A-17C show side sectional views of the light emitting diodeincluding the light emitting element, the printed circuit board, and thelens, according to the sixth exemplary embodiment of the presentdisclosure.

FIGS. 17A to 17C show the light emitting diode, in which the lightemitting element 10 according to the sixth exemplary embodiment ismounted on the printed circuit board 1200 shown in FIGS. 14A-14C, and adome-shaped lens 1310 is formed on the light emitting element 10. Asshown in FIGS. 17A to 17C, the light emitting element 10 may cover theentire upper surface of the printed circuit board 1200, and the firstand second electrode pads 39, 41 of the light emitting element 10 maydirectly contact the lead portions 1205 of the printed circuit board tobe electrically connected thereto. The heat dissipation pad 43 maydirectly contact the dissipation portion 1207 of the printed circuitboard 1200, or may be directly formed on the printed circuit board 1200in an exemplary embodiment wherein the printed circuit board 1200 isformed of a metal.

As described in the sixth exemplary embodiment, the dome-shaped lens1310 or the concave lens 1320 may contain phosphors that convertwavelengths of light emitted from the light emitting element 10. Thephosphors enable light emitted from the light emitting element 10 to berealized as various colors, particularly, mixed light such as whitelight.

FIG. 18 is a plan view of a light emitting element according to aseventh exemplary embodiment of the present disclosure and FIG. 19 is aschematic plan view of the light emitting element according to theseventh exemplary embodiment of the present disclosure. FIG. 20A is across-sectional view taken along line A-A′ of FIG. 18, FIG. 20B is across-sectional view taken along line B-B′ of FIG. 18, and FIG. 20C is across-sectional view taken along line C-C′ of FIG. 18. FIG. 21 is ananalysis picture showing ohmic contact between a first contact electrodeand a first conductive type semiconductor layer in the light emittingelement according to the seventh exemplary embodiment and FIG. 22 is ananalysis picture showing one edge end of the light emitting elementaccording to the seventh exemplary embodiment. FIG. 23 is an analysispicture showing ohmic contact between the first contact electrode and asecond contact electrode in the light emitting element according to theseventh exemplary embodiment.

Referring to FIG. 18 to FIG. 20B, the light emitting element 10according to the seventh exemplary embodiment includes first to thirdlight emitting cells C1, C2, C3, a first electrode connection D1, asecond electrode connection D2, a first electrode pad, 39 and a secondelectrode pad 41.

As shown in FIG. 18 and FIG. 19, in the light emitting element 10according to the seventh exemplary embodiment, the first to third lightemitting cells C1, C2, C3 are electrically connected to each other inseries and have substantially the same size. The first to third lightemitting cells C1, C2, C3 are disposed parallel to one another andarranged adjacent to one another.

The first light emitting cell C1 is electrically connected to the secondlight emitting cell C2 by the first electrode connection D1 and thesecond light emitting cell C2 is electrically connected to the thirdlight emitting cell C3 by the second electrode connection D2. That is,the first to third light emitting cells C1, C2, C3 are electricallyconnected to one another in series by the first and second electrodeconnections D1, D2.

The first and second electrode pads 39, 41 are formed to partially coverthe first to third light emitting cells C1, C2, C3 and are separatedfrom one another by a predetermined distance. The first and secondelectrode pads 39, 41 are connected to an external power source tosupply electric power to the light emitting element 10.

The second electrode pad 41 is electrically connected to the first lightemitting cell C1 and the third light emitting cell C3. That is, as shownin FIG. 19, electric current supplied from an external power sourceflows to the first light emitting cell C1, the second light emittingcell C2 and the third light emitting cell C3 through the secondelectrode pad 41 and finally flows to the first electrode pad 39. Here,in order to allow electric current flowing from the second electrode pad41 to be uniformly distributed to the first to third light emittingcells C1, C2, C3, the first electrode connection D1 and the secondelectrode connection D2 are disposed to be separated from each other asfar as possible.

Specifically, the first electrode connection D1 is formed on an uppersurface of the second light emitting cell C2 and the second electrodeconnection D2 is formed on an upper surface of the third light emittingcell C3 such that the first electrode connection D1 electricallyconnects the first and second light emitting cells C1, C2 to each otherand the second electrode connection D2 electrically connects the secondand third light emitting cells C2, C3 to each other. In order to disposethe first electrode connection D1 and the second electrode connection D2to be separated as far as possible with reference to the second lightemitting cell, the first and second electrode connections D1, D2 may bearranged as follows. With reference to the second light emitting cellC2, the first electrode connection D1 is disposed at one side of thesecond light emitting cell C2 and the second electrode connection D2 isdisposed at the other side of the second light emitting cell C2.Further, in order to dispose the first electrode connection D1 and thesecond electrode connection D2 to be separated as far as possible withreference to the second light emitting cell, the first and secondelectrode connections D1, D2 may be disposed in the diagonal directionwith reference to the second light emitting cell C2.

As shown in FIG. 18, in the light emitting element 10 according to theseventh exemplary embodiment, three light emitting cells C1, C2, C3 arearranged in series. Since the first light emitting cell C1 iselectrically connected to the second electrode pad 41, the firstelectrode connection D1 may be formed at a location where the firstlight emitting cell C1 is not electrically connected to the secondelectrode pad 41. Further, in order to dispose the first electrodeconnection D1 and the second electrode connection D2 to be separatedfrom each other as far as possible, the second electrode connection D2may be disposed in the diagonal direction of the first electrodeconnection D1 with reference to the second light emitting cell C2. Inthis structure, the second electrode connection D2 may be formed on aportion of the third light emitting cell C3 and the third light emittingcell C3 may be electrically connected to the first electrode pad 39 at alocation where the second electrode connection D2 is not formed.

Accordingly, as shown in FIG. 19, electric current can flow through theoverall region of the first to third light emitting cells C1, C2, C3.

Here, the first electrode pad 39 and the second electrode pad 41 aredisposed over the first to third light emitting cells C1, C2, C3,whereby heat caused by application of electric current to the first tothird light emitting cells C1, C2, C3 can be more effectively dischargedto the outside.

Referring to FIGS. 20A-20B, details of the first to third light emittingcells C1, C2, C3 will be described.

As shown in FIG. 20A, each of the first to third light emitting cellsC1, C2, C3 includes a substrate 21, a light emitting structure 23, afirst contact electrode 31, a second contact electrode 33, a firstinsulation layer 35, a second insulation layer 37, a third insulationlayer, a first electrode pad 39, and a second electrode pad 41.

The substrate 21 may be any substrate which allows growth of the lightemitting structure 23 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, and an aluminum nitride substrate. In the seventhexemplary embodiment, the substrate 21 may include a plurality ofpatterns 21 a on an upper surface thereof. As shown in FIG. 20A, thepatterns 21 a on the upper surface of the substrate 21 may be composedof or include a plurality of protrusions, and each of the patterns 21 amay have a peak or a flat plane on an upper surface thereof. Here, asshown in FIG. 20A and FIG. 22, the patterns 21 a formed on the uppersurface of the substrate 21 may have a small size in a region of thesubstrate 21 where the light emitting structure 23 is not formed.

The substrate 21 may be separated from the light emitting structure 23using a technique known in the art, as needed, whereby the lightemitting structure 23 may have a rough region formed on a lower surfacethereof.

The light emitting structure 23 includes a first conductive typesemiconductor layer 25, an active layer 27 disposed on the firstconductive type semiconductor layer 25, and a second conductive typesemiconductor layer 29 disposed on the active layer 27.

The light emitting structure 23 may include a partially exposed regionof the first conductive type semiconductor layer 25 formed by partiallyremoving the second conductive type semiconductor layer 29 and theactive layer 27. That is, as shown in FIG. 20A, a plurality of holes hmay be formed through the second conductive type semiconductor layer 29and the active layer 27 to expose the first conductive typesemiconductor layer 25. Here, the shape and arrangement of the holes hmay be modified in various ways.

The light emitting structure 23 may include a mesa which includes theactive layer 27 and the second conductive type semiconductor layer 29and may further includes a portion of the first conductive typesemiconductor layer 25. A first hole h1 may be formed in the mesa so asto expose the first conductive type semiconductor layer 25 and may beformed in plural.

The first contact electrode 31 and the second contact electrode 33 mayform ohmic contact with the first conductive type semiconductor layer 25and the second conductive type semiconductor layer 29, respectively.First, the second contact electrode 33 will be described. The secondcontact electrode 33 is formed to cover an upper surface of the secondconductive type semiconductor layer 29 and may be formed on an uppersurface of the mesa.

The second contact electrode 33 may be formed of any material capable offorming ohmic contact with the second conductive type semiconductorlayer 29 and may include, for example, at least one of a metallicmaterial or a conductive oxide. In the structure wherein the secondcontact electrode 33 includes a metallic material, the second contactelectrode 33 may include a reflective layer (not shown), which formsohmic contact with the second conductive type semiconductor layer 29,and a cover layer (not shown) covering the reflective layer to protectthe reflective layer. The reflective layer may include a metal and maybe composed of a single layer or multiple layers. In the structurewherein the second contact electrode 33 is composed of multiple layers,the second contact electrode 33 may include Ti, Ni or Au, and may have astructure wherein Au and Ti layers are sequentially stacked on a stackstructure of Ti and Ni layers alternately stacked one above another.

The first insulation layer 35 may be formed on an upper surface of thelight emitting structure 23 to cover the second contact electrode 33.The first insulation layer 35 may be formed to cover side surfaces ofthe first holes h formed in the mesa. Further, as shown in FIG. 20B andFIG. 20C, the first insulation layer 35 may be formed with second holesh2 which partially expose the second contact electrode 33. With thisstructure, the first contact electrode 31 of the light emitting celladjacent to the second contact electrode 33 can form ohmic contactthrough the second holes h2.

The first insulation layer 35 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The first insulationlayer 35 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked.

In addition, as shown in FIG. 20A to FIG. 20C, the first insulationlayer 35 may be formed to cover a portion of the substrate 21. Thestructure of the first insulation layer 35 can vary depending upon chipunit isolation in fabrication of the light emitting element 10. When thefirst insulation layer 35 is formed after chip unit isolation of a waferin fabrication of the light emitting element 10, the first insulationlayer 35 may be formed to cover a portion of the substrate 21. Thus, thefirst insulation layer 35 may be formed to cover a side surface of thelight emitting structure 23 exposed through the side surface of thesubstrate 21 while covering the substrate at opposite ends of the lightemitting element 10.

When the first insulation layer 35 is formed to cover a portion of thesubstrate 21, the first insulation layer 35 may be formed to cover somepatterns 21 a formed on the substrate 21 instead of covering all of thepatterns 21 a. Accordingly, some patterns 21 a of the substrate 21 maybe exposed towards an upper side of the first insulation layer 35 at thecorresponding locations.

As shown in FIG. 20C, the first insulation layer 35 may be formed tocover a portion of the substrate 21 in a separation space between thelight emitting cells.

The first insulation layer 35 may include a pre-insulation layer 35 aand a main insulation layer 35 b. The pre-insulation layer 35 a may beformed prior to the main insulation layer 35 b and thus may be disposedunder the main insulation layer 35 b.

The pre-insulation layer 35 a may cover a portion of the light emittingstructure 23 and may be formed to cover a portion of an upper surface ora side surface of the second contact electrode 33. After thepre-insulation layer 35 a is formed to cover the upper surface of thelight emitting structure 23, the pre-insulation layer 35 a may besubjected to etching so as to expose a portion of the second conductivetype semiconductor layer 29. The second contact electrode 33 may beformed on the exposed region of the second conductive type semiconductorlayer 29. As a result, the pre-insulation layer 35 a may be connected tothe second contact electrode 33.

The pre-insulation layer 35 a may be formed in the course of forming thesecond contact electrode 33. For example, in a structure wherein thesecond contact electrode 33 includes a conductive oxide layer (notshown) and a reflective electrode layer (not shown), the conductiveoxide layer may be formed on the second conductive type semiconductorlayer 29 and the pre-insulation layer 35 a may be formed beforeformation of the reflective electrode layer. After the reflectiveelectrode layer is formed, the main insulation layer 35 b is formed tocover the reflective electrode layer, thereby forming the firstinsulation layer 35. In this exemplary embodiment, the pre-insulationlayer 35 a may have a thickness of about 1,000 Å and the second contactelectrode 33 may have a thickness of about 11 kÅ.

In the seventh exemplary embodiment, the pre-insulation layer 35 a andthe main insulation layer 35 b may be formed of the same material, forexample, SiO₂.

Before formation of the main insulation layer 35 b, the periphery of thelight emitting element 10 may be etched for chip unit isolation of thelight emitting element 10, and during this process, the patterns 21 aexposed at the periphery of the substrate 21 may also be etched. Thus,the exposed patterns 21 a may have a smaller size than the patterns 21 acovered by the light emitting structure 23 as shown in FIG. 20A.

The first contact electrode 31 is formed on the upper surface of thefirst insulation layer 35 so as to cover the entirety of the firstinsulation layer 35 excluding a portion thereof. With this structure,the first contact electrode 31 can fill the first holes h1 formed in themesa and the second holes h2 formed in the first insulation layer 35.The first contact electrode 31 forms ohmic contact with the firstconductive type semiconductor layer 25 through the first holes h1 formedin the mesa, as shown in FIG. 20A. Further, as shown in FIG. 20B andFIG. 20C, the first contact electrode 31 may form ohmic contact with thesecond contact electrode 33 of another light emitting cell adjacentthereto through the second holes h2 formed in the first insulation layer35.

Here, in the course of etching the first insulation layer 35 to form thefirst holes h1 and the second holes h2, a portion of the surface of thefirst conductive type semiconductor layer 25 exposed through the firstholes h1 and a portion of the second contact electrode 33 exposedthrough the second holes h2 can also be etched together with the firstinsulation layer 35.

As such, in the course of etching the first insulation layer 35 to formthe first holes h1, the surface of the first conductive typesemiconductor layer 25 can also be partially etched together with thefirst insulation layer 35. Thus, as shown in FIG. 21, the firstconductive type semiconductor layer 25 may have a step at a locationthereof corresponding to the first holes h1.

As described above, when the second contact electrode 33 has thestructure wherein the Au and Ti layers are sequentially stacked on thestack structure of Ti and Ni layers alternately stacked one aboveanother, the Ti layer formed as the uppermost layer of the secondcontact electrode 33 may also be etched in the course of etching thefirst insulation layer 35. As a result, the uppermost layer of thesecond contact electrode 33 is the Ti layer in a region in which thefirst insulation layer 35 adjoins the second contact electrode 33, andthe uppermost layer of the second contact electrode 33 exposed throughthe second holes h2 is the Au layer. Thus, the first contact electrode31 can form ohmic contact with the uppermost layer of the second contactelectrode 33, that is, the Au layer, through the second holes h2. Here,while the first contact electrode 31 is etched, the prior uppermostlayer, that is, the Ti layer may be etched together with some of thesubsequent layer, that is, the Au layer. As a result, as shown in FIG.23, the first contact electrode 31 may have a step formed at a locationthereof corresponding to the second holes h2. Here, the first insulationlayer 35 may be subjected to dry etching.

In addition, the first contact electrode 31 is formed to cover theentirety of the first insulation layer 35 excluding a portion thereof,whereby light emitted from the light emitting structure 23 can bereflected by the first contact electrode 31. As shown in FIG. 20A toFIG. 20C, the first contact electrode 31 is formed to cover the sidesurface of the substrate 21 and the side surface of the separation spacebetween the light emitting cells, whereby light emitted from the lightemitting structure 23 can be reflected by the first contact electrode 31and emitted to the outside. As a result, luminous efficacy of the lightemitting element 10 can be maximized.

In this exemplary embodiment, the first contact electrode 31 acts as thefirst and second electrode connections D1, D2 of FIG. 18 and FIG. 19.That is, referring to FIG. 20C, the first contact electrode 31 of thefirst light emitting cell C1 extends to an upper surface of the secondcontact electrode 33 of the second light emitting cell C2 through theseparation space between the first light emitting cell C1 and the secondlight emitting cell C2. The first contact electrode 31 of the firstlight emitting cell C1 is formed to partially cover the mesa, the firstinsulation layer 35 and the second contact electrode 33 of the secondlight emitting cell C2, and forms ohmic contact with the second contactelectrode 33 of the second light emitting cell C2 through the secondholes h2 formed in the first insulation layer 35 of the second lightemitting cell C2. Further, the first contact electrode 31 of the secondlight emitting cell C2 is formed to cover the first insulation layer 35of the second light emitting cell C2 while being separated from thefirst contact electrode 31 of the first light emitting cell C1 by apredetermined distance.

As a result, the first contact electrode 31 may be formed to cover theside surface of another light emitting cell adjacent thereto, as shownin FIG. 20C. That is, the first contact electrode 31 of the first lightemitting cell C1 extends from the upper surface of the first lightemitting cell C1 to cover a portion of the second light emitting cell C2and a side surface of the second light emitting cell C2.

Further, as described above, the first contact electrode 31 may formohmic contact with the first conductive type semiconductor layer 25through the plurality of first holes h1, and, as shown in FIG. 19 andFIG. 20B, the first electrode connection D1 or the second electrodeconnection D2 may be disposed between the first holes h1. Specifically,referring to FIG. 20B, in the third light emitting cell C3, the firstcontact electrode 31 is formed to cover a plurality of mesas whileforming ohmic contact with the first conductive type semiconductor layer25 through the first holes h1. Here, the first contact electrode 31 ofthe second light emitting cell C2 may extend to form ohmic contact withthe second conductive type semiconductor layer 29 through the secondholes h2 disposed between the first holes h1, thereby forming the secondelectrode connection D2. In other words, the second electrode connectionD2 may be disposed between the first holes h1.

As described above, the first contact electrode 31 serves to form ohmiccontact with the first conductive type semiconductor layer 25 whilereflecting light. As a result, the first contact electrode 31 mayinclude a highly reflective metal layer such as an Al layer, and may becomposed of a single layer or multiple layers. Here, the highlyreflective metal layer may be formed on a contact layer such as a Ti, Cror Ni layer, and the first contact electrode 31 may include at least oneof Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag or Au.

The second insulation layer 37 is formed to cover the entire region ofthe first contact electrode 31 excluding some regions thereof. Thesecond insulation layer 37 may be formed with a first opening op1 thatpartially exposes the first contact electrode 31 and a second openingop2 that partially exposes the second contact electrode 33. Here, thesecond opening op2 may be formed through the first insulation layer 35,the first contact electrode 31 and the second insulation layer 37, andthe second insulation layer 37 may include one or more first openingsop1 and one or more second openings op2.

The first electrode pad 39 may form ohmic contact with the first contactelectrode 31 through the first openings op1 and the second electrode pad41 may form ohmic contact with the second contact electrode 33 throughthe second openings op2.

The second insulation layer 37 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The second insulationlayer 37 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked. In the structure wherein thesecond insulation layer 37 is composed of multiple layers, the uppermostlayer of the second insulation layer 37 is formed of SiN_(x). Thestructure wherein the uppermost layer of the second insulation layer 37is formed of SiN_(x) can more effectively prevent moisture penetrationinto the light emitting structure 23.

The first electrode pad 39 and the second electrode pad 41 may bedisposed on the second insulation layer 37 and electrically connected tothe first contact electrode 31 and the second contact electrode 33,respectively. As shown in FIG. 20A, the first electrode pad 39 may formohmic contact with the first contact electrode 31 through the firstopenings op1. In addition, the second electrode pad 41 may form ohmiccontact with the second contact electrode 33 through the second openingsop2.

The first electrode pad 39 is formed over the first to third lightemitting cells C1, C2, C3, and the first openings op1 are formed in thethird light emitting cell C3. With this structure, the first electrodepad 39 forms ohmic contact with the first contact electrode 31 of thethird light emitting cell C3. In addition, the second electrode pad 41is formed over the first to third light emitting cells C1, C2, C3 whilebeing separated from the first electrode pad 39 by a predetermineddistance or more, and the second openings op2 are formed in the firstlight emitting cell C1. With this structure, the second electrode pad 41forms ohmic contact with the second contact electrode 33 of the firstlight emitting cell C1.

The first openings op1 and the second openings op2 may be formed byetching the second insulation layer 37. The first contact electrode 31and the second contact electrode 33 exposed through the first and secondopenings op1, op2 may be etched in the course of etching the secondinsulation layer 37. That is, when each of the first and second contactelectrodes 31, 33 is composed of multiple layers including Ti, Ni andAu, the first and second contact electrodes 31, 33 may have a structurewherein Au and Ti layers are sequentially stacked on a stack structureof Ti and Ni layers alternately stacked one above another. Here, in eachof the first and second contact electrodes 31, 33, since the Ti layerformed as the uppermost layer may also be etched together with thesecond insulation layer 37 in the course of forming the first and secondopenings op1, op2, the uppermost layer of each of the first and secondcontact electrodes 31, 33 exposed through the first and second openingsop1, op2 is the Au layer. With this structure, the first and secondelectrode pads 39, 41 may form ohmic contact with the first and secondcontact electrodes 31, 33, the uppermost layer of which is the Au layer,through the first and second openings op1, op2. Here, the secondinsulation layer 37 may be subjected to dry etching.

In addition, each of the first electrode pad 39 and the second electrodepad 41 may be formed in the separation space between the first to thirdlight emitting cells C1, C2, C3. In some implementations, each of thefirst electrode pad 39 and the second electrode pad 41 may fill theseparation space between the first to third light emitting cells C1, C2,C3 and may have a thickness of dozens of micrometers, whereby the lightemitting element 10 can be used as a chip-scale package.

Each of the first electrode pad 39 and the second electrode pad 41 maybe composed of a single layer or multiple layers and may include anelectrically conductive material. For example, each of the firstelectrode pad 39 and the second electrode pad 41 may include at leastone of Cu, Pt, Au, Ti, Cr, Ni, Al or Ag, or may also include sinteredmetal particles and non-metallic materials interposed between metalparticles. Here, the first electrode pad 39 and the second electrode pad41 may be formed by plating, deposition, dotting, or screen printing,and the like.

Although not shown in the drawings, the light emitting element accordingto the seventh exemplary embodiment may further include a heatdissipation pad. In the light emitting element 10, the heat dissipationpad may be disposed between the first electrode pad 39 and the secondelectrode pad 41 to be separated from the first and second electrodepads 39, 41. The heat dissipation pad is disposed on the secondinsulation layer 37 to be insulated from other components. As a result,heat generated from the light emitting structure 23 can be transferredto the heat dissipation pad through the second insulation layer 37.

The heat dissipation pad may include the same material as the first andsecond electrode pads 39, 41 and may be formed by the same method. Inthe seventh exemplary embodiment, the entirety of the first and secondelectrode pads 39, 41 and the heat dissipation pad may be formed tocover most of the light emitting element 10, for example, 50% or more ofthe light emitting element 10 in plan view.

The light emitting element 10 described above may be fabricated by thefollowing method. A light emitting structure 23 is grown on an uppersurface of a substrate 21 and is partially etched to form a mesa. As aresult, the light emitting structure 23 may include at least one mesa,and a first conductive type semiconductor layer 25, an active layer 27and a second conductive type semiconductor layer 29 may be exposedthrough a side surface of the mesa. After the mesa is formed on thelight emitting structure 23, a pre-insulation layer 35 a is formed tocover an upper surface and a side surface of the mesa.

Thereafter, a portion of the pre-insulation layer 35 a on the mesa isremoved by etching, and a second contact electrode 33 is formed on anexposed upper surface of the second conductive type semiconductor layer29 formed by etching. After formation of the second contact electrode33, the light emitting element 10 is formed into individual chipsthrough chip unit isolation, whereby the light emitting element 10 isdivided into a plurality of light emitting cells.

Here, due to chip unit isolation of the light emitting element 10, theperiphery of the substrate 21 can be exposed together with a portion ofthe substrate between the light emitting cells, and some patterns formedon the upper surface of the substrate 21 may have a small size.

Then, a first insulation layer 35 (here, the first insulation layerrefers to the main insulation layer 35 b) is formed to cover the entireupper surface of the light emitting element 10 divided into a pluralityof light emitting cells and the light emitting structure 23 exposedthrough the side surface of the mesa. Here, the first insulation layer35 is formed to cover openings formed in the mesa and exposing the firstconductive type semiconductor layer 25. Then, first holes h1 are formedto expose the first conductive type semiconductor layer 25 by etchingthe first insulation layer 35 formed in the openings. Further, in orderto electrically connect adjacent light emitting cells to each other,second holes h2 are formed to expose a portion of the second contactelectrode 33 by partially etching the first insulation layer 35 coveringthe upper surface of the second contact electrode 33.

A first contact electrode 31 is formed to cover an upper surface of thefirst insulation layer 35 having the first holes h1 and the second holesh2 formed therein. The first contact electrode 31 may be formed over theentire region of the light emitting element 10 while forming in orfilling the separation space between the light emitting cells such thatlight emitted from the light emitting structure 23 can be reflected bythe first contact electrode 31. In addition, the first contact electrode31 of one of plural light emitting cells may be formed to cover aportion of another light emitting cell adjacent thereto such thatadjacent light emitting cells can be electrically connected to eachother. Here, the first contact electrodes 31 of the light emitting cellsare insulated from each other.

A second insulation layer 37 may be formed to cover an upper surface ofthe first contact electrode 31. The second insulation layer 37 may beformed to cover the entire region of the light emitting element 10including the first contact electrode 31. After formation of the secondinsulation layer 37, in order to form a first electrode pad 39 and asecond electrode pad 41 on the light emitting element 10, a firstopening op1 is formed in the second insulation layer 37 of one of thelight emitting cells included in the light emitting element 10 byetching the second insulation layer 37 so as to expose the first contactelectrode 31. Then, a second opening op1 is formed in the secondinsulation layer 37 of another light emitting cell by etching the secondinsulation layer 37 so as to expose the second contact electrode 33. Thefirst opening op1 and the second opening op2 may be formed in plural.

Then, the first electrode pad 39 is formed on an upper surface of thesecond insulation layer 37 to form ohmic contact with the first contactelectrode 31 exposed through the first openings op1, and the secondelectrode pad 41 is formed on the upper surface of the second insulationlayer 33 to form ohmic contact with the second contact electrode 33exposed through the second openings op2.

As needed, a heat dissipation pad may be formed between the first andsecond electrode pads 39, 41 on the second insulation layer 37.

FIG. 24 is a plan view of a light emitting element according to aneighth exemplary embodiment of the present disclosure.

Referring to FIG. 24, the light emitting element 10 according to theeighth exemplary embodiment includes first to seventh light emittingcells C1, C2, C3, C4, C5, C6, C7, first to sixth electrode connectionsD1, D2, D3, D4, D5, D6, a first electrode pad 39, and a second electrodepad 41.

As shown therein, the first to seventh light emitting cells C1, C2, C3,C4, C5, C6, C7 are disposed coplanar with one another and electricallyconnected to one another. The first to seventh light emitting cells C1,C2, C3, C4, C5, C6, C7 may have substantially the same size. For seriesconnection among the first to seventh light emitting cells C1, C2, C3,C4, C5, C6, C7, these light emitting cells are electrically connected toone another by the first to sixth electrode connections D1, D2, D3, D4,D5, D6.

Thus, the first light emitting cell C1 is electrically connected to thesecond light emitting cell C2 by the first electrode connection D1.Here, the second light emitting cell C2 is disposed under the firstlight emitting cell C1 and the first electrode connection D1 is disposedat an upper right side of the second light emitting cell C2. The secondlight emitting cell C2 is electrically connected to the third lightemitting cell C3 by the second electrode connection D2. Here, the thirdlight emitting cell C3 is disposed at the right side of the second lightemitting cell C2 and the second electrode connection D2 is disposed at alower left side of the third light emitting cell C3.

The third light emitting cell C3 is electrically connected to the fourthlight emitting cell C4 by the third electrode connection D3. Here, thefourth light emitting cell C4 is disposed on the third light emittingcell C3 and the third electrode connection D3 is disposed at a lowerright side of the fourth light emitting cell C4. In this arrangement,the fourth light emitting cell C4 is disposed at the right side of thefirst light emitting cell C1.

The fourth light emitting cell C4 is electrically connected to the fifthlight emitting cell C5 by the fourth electrode connection D4. Here, thefifth light emitting cell C5 is disposed at the right side of the fourthlight emitting cell C4 and the fourth electrode connection D4 isdisposed at an upper left side of the fifth light emitting cell C5. Thefifth light emitting cell C5 may have a narrower width and a longerlength than the fourth light emitting cell C4.

The fifth light emitting cell C5 is electrically connected to the sixthlight emitting cell C6 by the fifth electrode connection D5. Here, thesixth light emitting cell C6 is disposed at the right side of the fifthlight emitting cell C5 and the fifth electrode connection D5 is disposedat a lower left side of the sixth light emitting cell C6.

The sixth light emitting cell C6 is electrically connected to theseventh light emitting cell C7 by the sixth electrode connection D6.Here, the seventh light emitting cell C7 is disposed under the fifth andsixth light emitting cells C5, C6 and the sixth electrode connection D6is disposed at an upper right side of the seventh light emitting cellC7. The seventh light emitting cell C7 has the same width as the sum ofwidths of the fifth and sixth light emitting cells C5, C6, and a shorterlength than any other light emitting cells.

The first to seventh light emitting cells C1, C2, C3, C4, C5, C6, C7 areconnected to each other in series to constitute one light emittingelement 10.

The first to sixth electrode connections D1, D2, D3, D4, D5, D6 aredisposed on the second to seventh light emitting cells C2, C3, C4, C5,C6, C7, respectively. To this end, the first contact electrode 31extends to an upper surface of another light emitting cell adjacentthereto, thereby minimizing loss of light in the light emitting element10 despite the separation space between the light emitting cells.

The first to sixth electrode connections D1, D2, D3, D4, D5, D6 aredisposed such that adjacent electrode connections can be separated fromeach other as far as possible. For example, with reference to the secondlight emitting cell C2, the first electrode connection D1 is disposed atthe upper right side of the second light emitting cell C2 and the secondelectrode connection D2 is disposed at the lower right side of thesecond light emitting cell C2. As a result, electric current applied tothe second light emitting cell C2 through the first electrode connectionD1 flows to the second electrode connection D2 throughout the secondlight emitting cell C2. That is, the first electrode connection D1 isdisposed at a corner of one surface of the second light emitting cell C2and the second electrode connection D2 is disposed at a corner ofanother surface of the first electrode connection D1.

Further, with reference to the third light emitting cell C3, the secondelectrode connection D2 is disposed at the lower left side of the thirdlight emitting cell C3 and the third electrode connection D3 is disposedat the upper right side of the third light emitting cell C3. As aresult, with reference to the third light emitting cell C3, the secondelectrode connection D2 and the third electrode connection D3 aredisposed in the diagonal direction, whereby electric current applied tothe third light emitting cell C3 through the second electrode connectionD2 can flow to the third electrode connection D3 through the third lightemitting cell C3.

FIG. 25 is a plan view of a light emitting element according to a ninthexemplary embodiment of the present disclosure and FIG. 26 is aschematic plan view of the light emitting element according to the ninthexemplary embodiment of the present disclosure. FIG. 27A is across-sectional view taken along line A-A′ of FIG. 25, FIG. 27B is across-sectional view taken along line B-B′ of FIG. 25, and FIG. 27C is across-sectional view taken along line C-C′ of FIG. 25.

As shown in FIG. 25 to FIG. 27C, the light emitting element 10 accordingto a ninth exemplary embodiment includes first to fourth light emittingcells C1, C2, C3, C4, first to third electrode connections D1, D2, D2, afirst electrode pad 39, a second electrode pad 41, and a heatdissipation pad 43.

As shown in FIG. 25 and FIG. 26, in the light emitting element 10according to the ninth exemplary embodiment, the first to fourth lightemitting cells C1, C2, C3, C4 are electrically connected to each otherin series and have substantially the same area. Thus, in the ninthexemplary embodiment, four light emitting cells C1, C2, C3, C4 aredisposed adjacent to one another and the arrangement of four lightemitting cells C1, C2, C3, C4 has a shape substantially similar to asquare.

Here, among the four light emitting cells C1, C2, C3, C4, the firstlight emitting cell C1 may be disposed at the upper right side and thesecond light emitting cell C2 may be disposed at the lower right side inFIG. 25 and FIG. 26. The third light emitting cell C3 may be disposed atthe upper left side and the fourth light emitting cell C4 may bedisposed at the lower left side.

Further, the first light emitting cell C1 is electrically connected tothe second light emitting cell C2 by the first electrode connection D1;the second light emitting cell C2 is electrically connected to the thirdlight emitting cell C3 by the second electrode connection D2; and thethird light emitting cell C3 is electrically connected to the fourthlight emitting cell C4 by the third electrode connection D3. That is,the first to fourth light emitting cells C1, C2, C3, C4 are electricallyconnected to each other by the first to third electrode connections D1,D2, D3.

In the above arrangement of the first to fourth light emitting cells C1,C2, C3, C4, the first light emitting cell C1 and the second lightemitting cell C2 are disposed such that one side of the first lightemitting cell C1 faces one side of the second light emitting cell C2,and the third light emitting cell C3 and the fourth light emitting cellC4 are also disposed such that one side of the third light emitting cellC3 faces one side of the fourth light emitting cell C4. However, thesecond light emitting cell C2 and the third light emitting cell C3 arenot disposed such that one side of the second light emitting cell C2faces one or the other side of the third light emitting cell C3.Accordingly, the first electrode connection D1 electrically connectingthe first light emitting cell C1 to the second light emitting cell C2 isdisposed on the second light emitting cell C2 and extends from one sideof the first light emitting cell C1 towards the second light emittingcell C2. The third electrode connection D3 electrically connecting thethird light emitting cell C3 to the fourth light emitting cell C4 isdisposed on the fourth light emitting cell C4.

However, the second light emitting cell C2 and the third light emittingcell C3 are not disposed to be adjacent each other such that one side ofthe second light emitting cell C2 faces one or the other side of thethird light emitting cell C3. The second electrode connection D2 isdisposed on the third light emitting cell C3. To this end, the firstcontact electrode 31 of the second light emitting cell C2 extends fromthe second light emitting cell C2 to the second electrode connection D2disposed on the third light emitting cell C3.

Referring to FIG. 25 and FIG. 26, the second electrode connection D2 isformed on the right side of the third light emitting cell C3, and anextension portion 31 a of the first contact electrode 31 of the secondlight emitting cell C2 extends to a space between the first contactelectrode 31 of the first light emitting cell C1 and the first contactelectrode 31 of the third light emitting cell C3 and is electricallyconnected to the second electrode connection D2. The extension portion31 a is separated and insulated from the first contact electrode 31 ofthe first light emitting cell C1 and the first contact electrode 31 ofthe third light emitting cell C3. The first contact electrode 31 of eachof the light emitting cells C1, C2, C3, C4 will be described in moredetail below.

As described above, the first to third electrode connections D1, D2, D3are formed on the second to fourth light emitting cells C2, C3, C4,respectively. In some implementations, the first to third electrodeconnections D1, D2, D3 are formed on the sides of the second to fourthlight emitting cells C2, C3, C4 adjacent to the first to third lightemitting cells C1, C2, C3, respectively. Further, in the structurewherein each of the first to third electrode connections D1, D2, D3 isprovided in plural, each of the first to third electrode connections D1,D2, D3 is disposed along the corresponding side of each of the second tofourth light emitting cells C2, C3, C4 to be separated from one another.

The first electrode pad 39 and the second electrode pad 41 are formed topartially cover the fourth light emitting cell C4 and the first lightemitting cell C1, respectively. The first electrode pad 39 is disposedat a corner of the fourth light emitting cell C4 to be electricallyconnected to the fourth light emitting cell C4, and the second electrodepad 41 is disposed at a corner of the first light emitting cell C1 to beelectrically connected to the first light emitting cell C1.

In the ninth exemplary embodiment, the first and second electrode pads39, 41 have a triangular shape and are arranged so as to be separatedfrom each other as far as possible in a plan view of the light emittingelement 10. Further, the heat dissipation pad 43 may be formed in ahexagonal shape between the first electrode pad 39 and the secondelectrode pad 41. Here, the shapes of the first electrode pad 39, thesecond electrode pad 41 and the heat dissipation pad 43 are not limitedto the shapes shown in the drawings and may be changed in various ways,as needed. Further, the first electrode pad 39, the second electrode pad41 and the heat dissipation pad 43 may be separated from one another bya predetermined distance.

In the ninth exemplary embodiment, the heat dissipation pad 43 is formedto cover most of the first to fourth light emitting cells C1, C2, C3, C4by covering the entirety of the second light emitting cell C2 and thethird light emitting cell C3 on which the first electrode pad 39 and thesecond electrode pad 41 are not disposed. With this structure, the heatdissipation pad 43 is formed such that at least three sides of the heatdissipation pad 43 are exposed to the outside in a plan view of thelight emitting element 10, and may have, for example, a hexagonal shape.As such, the heat dissipation pad 43 is formed over the first to fourthlight emitting cells C1, C2, C3, C4, whereby heat caused by applicationof electric current to the first to fourth light emitting cells C1, C2,C3, C4 can be more effectively discharged.

Referring to FIGS. 27A-27C, details of the first to fourth lightemitting cells C1, C2, C3, C4 will now be described.

Referring to FIG. 27A, each of the first to fourth light emitting cellsC1, C2, C3, C4 includes a substrate 21, a light emitting structure 23, afirst contact electrode 31, a second contact electrode 33, a firstinsulation layer 35, a second insulation layer 37, a first electrode pad39, a second electrode pad 41, and a heat dissipation pad 43. Indescription of the first to fourth light emitting cells C1, C2, C3, C4,descriptions of the same components as those of the above exemplaryembodiments will be omitted.

The substrate 21 may be any substrate which allows growth of the lightemitting structure 23 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, and an aluminum nitride substrate. In the ninthexemplary embodiment, the substrate 21 may include a plurality ofpatterns 21 a on an upper surface thereof. As shown in FIG. 27A, thepatterns 21 a formed on the upper surface of the substrate 21 mayinclude a plurality of protrusions, and each of the patterns 21 a mayhave a peak or a flat plane on an upper surface thereof. Here, theplurality of patterns 21 a formed on the upper surface of the substrate21 may have a small size in a region of the substrate 21 where the lightemitting structure 23 is not formed.

The substrate 21 may be separated from the light emitting structure 23using a technique known in the art, as needed, whereby the lightemitting structure 23 may have a rough region formed on a lower surfacethereof.

The light emitting structure 23 includes a first conductive typesemiconductor layer 25, an active layer 27 disposed on the firstconductive type semiconductor layer 25, and a second conductive typesemiconductor layer 29 disposed on the active layer 27.

The light emitting structure 23 may include a partially exposed regionof the first conductive type semiconductor layer 25 formed by partiallyremoving the second conductive type semiconductor layer 29 and theactive layer 27. That is, as shown in FIG. 27A, first holes h may beformed through the second conductive type semiconductor layer 29 and theactive layer 27 to expose the first conductive type semiconductor layer25. Here, the shape and arrangement of the first holes h1 may bemodified in various ways.

The light emitting structure 23 may include a mesa which includes theactive layer 27 and the second conductive type semiconductor layer 29and may further includes a portion of the first conductive typesemiconductor layer 25. The first holes h1 may be formed in the mesa soas to expose the first conductive type semiconductor layer 25 and may beformed in plural.

The first contact electrode 31 and the second contact electrode 33 mayform ohmic contact with the first conductive type semiconductor layer 25and the second conductive type semiconductor layer 29, respectively.First, the second contact electrode 33 will be described. The secondcontact electrode 33 is formed to cover an upper surface of the secondconductive type semiconductor layer 29 and may be formed on an uppersurface of the mesa.

The second contact electrode 33 may be formed of any material capable offorming ohmic contact with the second conductive type semiconductorlayer 29 and may include, for example, at least one of a metallicmaterial and a conductive oxide.

The first insulation layer 35 may be formed on an upper surface of thelight emitting structure 23 to cover the second contact electrode 33.The first insulation layer 35 may be formed to cover side surfaces ofthe first holes h formed in the mesa. Further, as shown in FIG. 27B andFIG. 27C, the first insulation layer 35 may be formed with second holesh2 which partially expose the second contact electrode 33. With thisstructure, the first contact electrode 31 of the light emitting celladjacent to the second contact electrode 33 can form ohmic contactthrough the second holes h2.

The first insulation layer 35 may include an insulation material, forexample, SiO₂, SiN_(x), or MgF₂, and the like. The first insulationlayer 35 may be composed of multiple layers and may include adistributed Bragg reflector in which materials having different indicesof refraction are alternately stacked.

In addition, as shown in FIG. 27A to FIG. 27C, the first insulationlayer 35 may be formed to cover a portion of the substrate 21. Thestructure of the first insulation layer 35 can vary depending upon chipunit isolation in fabrication of the light emitting element 10. When thefirst insulation layer 35 is formed after chip unit isolation of a waferin fabrication of the light emitting element 10, the first insulationlayer 35 may be formed to cover a portion of the substrate 21. Thus, thefirst insulation layer 35 may be formed to cover a side surface of thelight emitting structure 23 exposed through the side surface of thesubstrate 21 while covering the substrate at opposite ends of the lightemitting element 10.

When the first insulation layer 35 is formed to cover a portion of thesubstrate 21, the first insulation layer 35 may be formed to cover somepatterns 21 a formed on the substrate 21 instead of covering all of thepatterns 21 a. Accordingly, some patterns 21 a of the substrate 21 maybe exposed towards an upper side of the first insulation layer 35 at thecorresponding locations.

As shown in FIG. 27C, the first insulation layer 35 may be formed tocover a portion of the substrate 21 in a separation space between thelight emitting cells.

The first insulation layer 35 may include a pre-insulation layer 35 aand a main insulation layer 35 b. The pre-insulation layer 35 a may beformed prior to the main insulation layer 35 b and thus may be disposedunder the main insulation layer 35 b.

The pre-insulation layer 35 a may cover a portion of the light emittingstructure 23 and may be formed to cover a portion of an upper surface ofthe second contact electrode 33 or a side surface thereof. After thepre-insulation layer 35 a is formed to cover the upper surface of thelight emitting structure 23, the pre-insulation layer 35 a may besubjected to etching so as to expose a portion of the second conductivetype semiconductor layer 29. The second contact electrode 33 may beformed on the exposed region of the second conductive type semiconductorlayer 29. As a result, the pre-insulation layer 35 a may be connected tothe second contact electrode 33.

The pre-insulation layer 35 a may be formed in the course of forming thesecond contact electrode 33. For example, in a structure wherein thesecond contact electrode 33 includes a conductive oxide layer (notshown) and a reflective electrode layer (not shown), the conductiveoxide layer may be formed on the second conductive type semiconductorlayer 29 and the pre-insulation layer 35 a may be formed beforeformation of the reflective electrode layer. After the reflectiveelectrode layer is formed, the main insulation layer 35 b is formed tocover the reflective electrode layer, thereby forming the firstinsulation layer 35.

In the ninth exemplary embodiment, the pre-insulation layer 35 a and themain insulation layer 35 b may be formed of or include the samematerial, for example, SiO₂.

Before formation of the main insulation layer 35 b, the periphery of thelight emitting element 10 may be etched for chip unit isolation of thelight emitting element 10, and during this process, the patterns 21 aexposed at the periphery of the substrate 21 may also be etched. Thus,the exposed patterns 21 a may have a smaller size than the patterns 21 acovered by the light emitting structure 23 as shown in FIG. 27A.

The first contact electrode 31 is formed on the upper surface of thefirst insulation layer 35 so as to cover the entirety of the firstinsulation layer 35 excluding a portion thereof. With this structure,the first contact electrode 31 can be formed in or fill the first holesh1 formed in the mesa and the second holes h2 formed in the firstinsulation layer 35. The first contact electrode 31 forms ohmic contactwith the first conductive type semiconductor layer 25 through the firstholes h1 in the mesa, as shown in FIG. 27A. Further, as shown in FIG.27B and FIG. 27C, the first contact electrode 31 may form ohmic contactwith the second contact electrode 33 of another light emitting celladjacent thereto through the second holes h2 in the first insulationlayer 35.

In addition, the first contact electrode 31 is formed to cover theentirety of the first insulation layer 35 excluding a portion thereof,whereby light emitted from the light emitting structure 23 can bereflected by the first contact electrode 31. As shown in FIG. 27A toFIG. 27C, the first contact electrode 31 is formed to cover the sidesurface of the substrate 21 and a side surface of the separation spacebetween the light emitting cells, whereby light emitted from the lightemitting structure 23 can be reflected by the first contact electrode 31and emitted to the outside. As a result, luminous efficacy of the lightemitting element 10 can be maximized.

In this exemplary embodiment, the first contact electrode 31 acts as thefirst to third electrode connections D1, D2, D3 extending from the firstto third light emitting cells C1, C2, C3, respectively, as shown in FIG.25 and FIG. 26. That is, referring to FIG. 27B, the first contactelectrode 31 of the first light emitting cell C1 extends to an uppersurface of the second light emitting cell C2, whereby the firstelectrode connection D1 is formed on the upper surface of the secondlight emitting cell C2. In addition, the first contact electrode 31extending from the first light emitting cell C1 forms ohmic contact withthe second contact electrode 33 on the upper surface of the second lightemitting cell C2.

Further, referring to FIG. 27C, the first contact electrode 31 of thefirst light emitting cell C1 is formed on an upper surface of the firstlight emitting cell C1, and the extension portion 31 a of the firstcontact electrode 31 extends from the second light emitting cell C2 tothe upper surface of the third light emitting cell C3 while filling theseparation space between the first light emitting cell C1 and the thirdlight emitting cell C3. With this structure, the extension portion 31 aof the second light emitting cell C2 forms ohmic contact with the secondcontact electrode 33 of the third light emitting cell C3 through thesecond holes h2 on the third light emitting cell C3, whereby the secondelectrode connection D2 can be formed on the upper surface of the thirdlight emitting cell C3. Here, the extension portion 31 a of the secondlight emitting cell C2 may be separated from the first contact electrode31 of the third light emitting cell C3 to be insulated therefrom, andmay extend to the upper surface of the first light emitting cell C1while being separated from the first contact electrode 31 of the firstlight emitting cell C1 to be insulated therefrom.

As described above, the first contact electrode 31 serves to form ohmiccontact with the first conductive type semiconductor layer 25 whilereflecting light. Thus, the first contact electrodes of the first tothird light emitting cells C1, C2, C3 extend to the second to fourthlight emitting cells C2, C3, C4 for electrical connection and cover mostof the light emitting element, thereby improving luminous efficacy ofthe light emitting element 10.

The first contact electrode 31 may include a highly reflective metallayer such as an Al layer, and may be composed of a single layer ormultiple layers. Here, the highly reflective metal layer may be formedon a contact layer such as a Ti, Cr or Ni layer, and the first contactelectrode 31 may include at least one of Ni, Pt, Pd, Rh, W, Ti, Al, Mg,Ag and Au.

The second insulation layer 37 is formed to cover the entire region ofthe first contact electrode 31 excluding some regions thereof. Thesecond insulation layer 37 may be formed with a first opening op1 thatpartially exposes the first contact electrode 31 and a second openingop2 that partially exposes the second contact electrode 33. Here, thesecond opening op2 may be formed through the first insulation layer 35,the first contact electrode 31 and the second insulation layer 37, andthe second insulation layer 37 may include one or more first openingsop1 and one or more second openings op2.

The first electrode pad 39 may form ohmic contact with the first contactelectrode 31 through the first openings op1 and the second electrode pad41 may form ohmic contact with the second contact electrode 33 throughthe second openings op2.

The first electrode pad 39, the second electrode pad 41 and the heatdissipation pad 43 are disposed on the second insulation layer 37 suchthat the first electrode pad 39 can be electrically connected to thefirst contact electrode 31 of the fourth light emitting cell C4 and thesecond electrode pad 41 can be electrically connected to the secondcontact electrode 33 of the first light emitting cell C1. As shown inFIG. 27A, the first electrode pad 39 may form ohmic contact with thefirst contact electrode 31 through the first openings op1. Further, thesecond electrode pad 41 may form ohmic contact with the second contactelectrode 33 through the second openings op2. The heat dissipation pad43 may be disposed on the second insulation layer while being insulatedfrom the first electrode pad 39 and the second electrode pad 41.

The first electrode pad 39 is formed on the fourth light emitting cellC4 and the first openings op1 are formed in the fourth light emittingcell C4. With this structure, the first electrode pad 39 forms ohmiccontact with the first contact electrode 31 of the fourth light emittingcell C4. Further, the second electrode pad 41 is formed on the firstlight emitting cell C1 so as to be separated from the heat dissipationpad 43 by a predetermined distance or more and the second openings op2are formed in the first light emitting cell C1. As a result, the secondelectrode pad 41 forms ohmic contact with the second contact electrode33 of the first light emitting cell C1.

Further, the heat dissipation pad 43 may be formed to fill theseparation spaces between the first to fourth light emitting cells C1,C2, C3, C4 and may have a thickness of dozens of micrometers. Further,like the heat dissipation pad 43, the first electrode pad 39 and thesecond electrode pad 41 have the same thickness, whereby the lightemitting element 10 can be used as a chip-scale package.

Each of the first electrode pad 39 and the second electrode pad 41 maybe composed of a single layer or multiple layers and may include anelectrically conductive material. For example, each of the firstelectrode pad 39 and the second electrode pad 41 may include at leastone of Cu, Pt, Au, Ti, Cr, Ni, Al or Ag, or may also include sinteredmetal particles and non-metallic materials interposed between metalparticles. Here, the first electrode pad 39 and the second electrode pad41 may be formed by plating, deposition, dotting, or screen-printing,and the like. Further, the heat dissipation pad 43 may include the samematerial as the first and second electrode pads 39, 41.

The light emitting element 10 described above may be fabricated by thesame method as in the seventh exemplary embodiment.

FIG. 28 is a plan view of a light emitting element according to a tenthexemplary embodiment of the present disclosure.

Referring to FIG. 28, the light emitting element 10 according to thetenth exemplary embodiment includes first to fourth light emitting cellsC1, C2, C3, C4, first to third electrode connections D1, D2, D3, a firstelectrode pad 39, and a second electrode pad 41. In description of thetenth exemplary embodiment, descriptions of the same components as thoseof the ninth exemplary embodiment will be omitted.

As shown therein, the first to fourth light emitting cells C1, C2, C3,C4 are disposed coplanar with each other so as to be electricallyconnected to each other and may have substantially the same area. Forseries connection between the first to fourth light emitting cells C1,C2, C3, C4, the light emitting cells C1, C2, C3, C4 are electricallyconnected to one another by the first to third electrode connections D1,D2, D3.

In the tenth exemplary embodiment, the first to fourth light emittingcells C1, C2, C3, C4 may be arranged in series in one direction.

Referring to FIG. 28, the second light emitting cell C2 is disposed atthe right side of the first light emitting cell C1 and is electricallyconnected to the first light emitting cell C1 by the first electrodeconnections D1. In addition, the third light emitting cell C3 isdisposed at the right side of the second light emitting cell C2 and iselectrically connected to the second light emitting cell C2 by thesecond electrode connections D2. The fourth light emitting cell C4 isdisposed at the right side of the third light emitting cell C3 and iselectrically connected to the third light emitting cell C3 by the thirdelectrode connections D3.

With this structure, the light emitting cells C1, C2, C3, C4 areconnected to one another in series to provide one light emitting element10.

The first to third electrode connections D1, D2, D3 are disposed on thesecond to fourth light emitting cells C2, C3, C4, respectively. To thisend, the first contact electrode 31 extends to an upper surface of ananother light emitting cell adjacent thereto, thereby minimizing loss oflight in the light emitting element 10 despite the separation spaceformed between the light emitting cells.

In the tenth exemplary embodiment, since the first to fourth lightemitting cells C1, C2, C3, C4 are formed to have directionality in onedirection, each of the first to third electrode connections D1, D2, D3is formed over one side of an adjacent light emitting cell. For example,the first electrode connections D1 are formed over one side of thesecond light emitting cell C2 adjacent to the first light emitting cellC1 so as to be spaced apart or separated from one another along one sideof the second light emitting cell C2. Thus, electric current can flowthrough the one side thereof between the first light emitting cell C1and the second light emitting cell C2.

The first electrode pad 39 may be formed to cover the entirety or aportion of the upper surfaces of the third light emitting cell C3 andthe fourth light emitting cell C4, and the second electrode pad 41 maybe formed to cover the entirety or a portion of the upper surfaces ofthe first light emitting cell C1 and the second light emitting cell C2.The first electrode pad 39 may be electrically connected to the fourthlight emitting cell C4 and the second electrode pad 41 may beelectrically connected to the first light emitting cell C1. The firstelectrode pad 39 and the second electrode pad 41 may be separated fromeach other by a predetermined distance or more.

Although not shown in FIG. 28, a heat dissipation pad may be disposedbetween the first electrode pad 39 and the second electrode pad 41, asneeded. In this case, the first electrode pad 39, the second electrodepad 41 and the heat dissipation pad may be separated from one another.

FIG. 29 is a plan view of a light emitting element according to aneleventh exemplary embodiment of the present disclosure.

Referring to FIG. 29, the light emitting element according to theeleventh exemplary embodiment includes first to eleventh light emittingcells C1 to C11, first to tenth electrode connections D1 to D10, a firstelectrode pad 39, a second electrode pad 41, and a heat dissipation pad43. In description of the eleventh exemplary embodiment, descriptions ofthe same components as those of the ninth exemplary embodiment will beomitted.

According to the eleventh exemplary embodiment, the light emittingelement includes eleven light emitting cells C1 to C11, which areconnected to each other in series. As shown in FIG. 29, the first toeleventh light emitting cells C1 to C11 may have similar sizes, in whichthe first to fifth light emitting cells C1 to C5 have the samerectangular shape and the sixth to eleventh light emitting cells C6 toC11 have the same rectangular shape, which is different from that of thefirst to firth light emitting cells C1 to C5, in consideration ofdisposition thereof.

Referring to FIG. 29, the first to eleventh light emitting cells C1 toC11 are arranged such that the first light emitting cell C1 is disposedat the uppermost side of the right side of the light emitting elementand the second to fifth light emitting cells C2 to C5 are sequentiallyarranged in the downward direction under the first light emitting cellC1. The sixth light emitting cell C6 is disposed at the left side of thefifth light emitting cell C5 and the seventh and eighth light emittingcells C7, C8 are sequentially arranged in the upward direction on thesixth light emitting cell C6.

The ninth light emitting cell C9 is disposed at the left side of theeighth light emitting cell C8 and the tenth and eleventh light emittingcells C10, C11 are sequentially arranged in the downward direction underthe ninth light emitting cell C9.

In such arrangement of the first to eleventh light emitting cells C1 toC11, the first to tenth electrode connections D1 to D10 electricallyconnect the light emitting cells C1 to C11 to one another. With thisstructure, the first to eleventh light emitting cells C1 to C11 areelectrically connected to one another and may be connected to oneanother in series in other exemplary embodiments.

In the eleventh exemplary embodiment, the first to tenth electrodeconnections D1 to D10 are formed on upper surfaces of the second toeleventh light emitting cells C2 to C11, respectively, and the first totenth electrode connections D1 to D10 may be formed in plural. That is,in the eleventh exemplary embodiment, the first to eleventh lightemitting cells C1 to C11 are disposed to be adjacent to one another suchthat one side of one light emitting cell faces one side of another lightemitting cell, whereby each of the first to tenth electrode connectionsD1 to D10 can be disposed along one side of each of the second toeleventh light emitting cells C2 to C11.

In arrangement of the fifth and sixth light emitting cells C5, C6, oneside of the fifth light emitting cell C5 partially faces one side of thesixth light emitting cell C6. Thus, the fifth electrode connections D5are formed on a portion of the one side of the sixth light emitting cellC6 facing one side of the fifth light emitting cell C5 instead of beingformed over the one side of the sixth light emitting cell C6.

The first electrode pad 39 is formed on the upper surface of theeleventh light emitting cell C11 so as to be electrically connected tothe first contact electrode 31 of the eleventh light emitting cell C11.In addition, the second electrode pad 41 is formed on the upper surfaceof the first light emitting cell C1 so as to be electrically connectedto the first contact electrode 31 of the first light emitting cell C1.Electrical connection between the first electrode pad 39 and theeleventh light emitting cell C11 and between the second electrode pad 41and the first light emitting cell C1 is the same as in the ninthexemplary embodiment, and thus detailed descriptions thereof will beomitted.

The heat dissipation pad 43 is disposed between the first and secondelectrode pads 39, 41 while being separated from the first electrode pad39 and the second electrode pad 41. With this structure, the heatdissipation pad 43 may be formed to cover some regions of the firstlight emitting cell C1 and the eleventh light emitting cell C11 and someor the entire region of the second to tenth light emitting cells C2 toC10.

FIG. 30 and FIG. 31 are plan views of a light emitting element accordingto a twelfth exemplary embodiment of the present disclosure. FIGS. 32 to37 are schematic cross-sectional views taken along the correspondinglines of FIG. 31.

Referring to FIG. 30, the light emitting element includes first tofourth light emitting cells 100, 200, 300, 400 disposed adjacent to oneanother in a first direction 1. In addition, the light emitting elementmay include a first electrode connection 150 electrically connecting thefirst light emitting cell 100 to the second light emitting cell 200, asecond electrode connection 250 electrically connecting the second lightemitting cell 200 to the third light emitting cell 300, and a thirdelectrode connection 350 electrically connecting the third lightemitting cell 300 to the fourth light emitting cell 400. Further, thelight emitting element may include a substrate 110, a first electrodepad 500, and a second electrode pad 600.

The substrate 110 may be any substrate which allows growth of the firstconductive type semiconductor layer 111, the active layer 112 and thesecond conductive type semiconductor layer 113 thereon, and may include,for example, a sapphire substrate, a silicon carbide substrate, agallium nitride substrate, an aluminum nitride substrate, or a siliconsubstrate.

In this exemplary embodiment, the substrate 110 may be a patternedsapphire substrate PSS. The substrate 110 may include rough patterns R1,R2 formed on an upper surface thereof. The rough patterns R1, R2 canimprove light extraction efficiency of a light emitting diode byeffectively reflecting light generated from the semiconductor layers.The rough patterns R1, R2 may have a triangular pyramid shape, aquadrangular pyramid shape, or a semispherical shape, without beinglimited thereto. The first rough pattern R1 may adjoin the firstconductive type semiconductor layers 111, 211, 311, 411 and may bedisposed on lower surfaces of the light emitting cells, specifically, onthe lower surfaces of the first conductive type semiconductor layers111, 211, 311, 411. The second rough pattern R2 does not adjoin thefirst conductive type semiconductor layers 111,211,311,411 and may bedisposed in regions between the light emitting cells.

The first rough pattern R1 may have a different height from the secondrough pattern R2. The second rough pattern R2 may have a smaller heightthan the first rough pattern R1. For example, the first rough pattern R1may have a height of 1.5 μm to 2 μm and the second rough pattern R2 mayhave a smaller height than the first rough pattern. Since the firstrough pattern R1 has a greater height, the first rough pattern R1 canmore effectively reflect light generated from the light emitting cells.

The first electrode connection 150 may include a first-1 electrodeconnection 140 disposed on the first light emitting cell 100, a first-2electrode connection 160 disposed on the second light emitting cell 200,and a first intermediate connection 106 interposed between the firstlight emitting cell 100 and the second light emitting cell 200 andconnecting the first-1 electrode connection 140 to the first-2 electrodeconnection 160. The first-1 electrode connection 140 may include first-1edge portions 102 and first-1 branches 103. Further, the first-2electrode connection 160 may include a second-1 edge portion 201 andsecond-1 branches 202.

The second electrode connection 250 may include a second-1 electrodeconnection 240 disposed on the second light emitting cell, a third-2electrode connection 260 disposed on the third light emitting cell, anda second intermediate connection 205 interposed between the second lightemitting cell 200 and the third light emitting cell 300 and connectingthe second-1 electrode connection 240 to the second-2 electrodeconnection 260, wherein the second-1 electrode connection may include asecond-1 edge portion 203 and second-1 branches 204. In addition, thesecond-2 electrode connection 260 may include a second-2 edge portion201 and second-2 branches 202.

The third electrode connection 350 may include a third-1 electrodeconnection 340 disposed on the third light emitting cell, a third-2electrode connection 401 disposed on the fourth light emitting cell, anda third intermediate connection 305 interposed between the third lightemitting cell 300 and the fourth light emitting cell 400 and connectingthe third-1 electrode connection 340 to the third-2 electrode connection401, wherein the third-1 electrode connection includes a third-1 edgeportion 303 and third-1 branches 304.

The first light emitting cell 100 includes a first side surface adjacentto the second light emitting cell 200, a second side surface facing thefirst side surface, and a third side surface and a fourth side surfacedisposed between the first side surface and the second side surface andfacing each other. The second light emitting cell 200 includes a firstside surface adjacent to the first light emitting cell 100, a secondside surface facing the first side surface, a third side surfacedisposed between the first side surface and the second side surface andadjacent to the third side surface of the first light emitting cell 100,and a fourth side surface facing third side surface. The third lightemitting cell 300 includes a first side surface adjacent to the secondlight emitting cell 200, a second side surface facing the first sidesurface, a third side surface disposed between the first side surfaceand the second side surface and adjacent to the third side surface ofthe second light emitting cell 200, and a fourth side surface facing thethird side surface.

Referring to FIG. 30, FIG. 32, and FIG. 33, the first light emittingcell 100 includes a first conductive type semiconductor layer 111, anactive layer 112 disposed on the first conductive type semiconductorlayer 111, and a second conductive type semiconductor layer 113 disposedon the active layer 112. Further, the first light emitting cell 100includes a pre-insulation layer 114 described below, a contact electrode115, a first insulation layer 116, and a second insulation layer 117.

The first conductive type semiconductor layer 111, the active layer 112and the second conductive type semiconductor layer 113 may include aIII-V based compound semiconductor, for example, a nitride semiconductorsuch as (Al, Ga, In)N. The first conductive type semiconductor layer 111may include an n-type dopant (for example, Si) and the second conductivetype semiconductor layer 113 may include a p-type dopant (for example,Mg), or vice versa. The active layer 112 may include a multi-quantumwell (MQW) structure and the composition ratio of the active layer maybe determined so as to emit light in a desired wavelength range.

Further, the first light emitting cell 100 may include a partiallyexposed region of the first conductive type semiconductor layer 111formed by partially removing the second conductive type semiconductorlayer 113 and the active layer 112. For example, as shown in FIG. 30 andFIG. 32, the first light emitting cell 100 may include a plurality ofcontact holes 104 formed through the second conductive typesemiconductor layer 113 and the active layer 112 to expose the firstconductive type semiconductor layer 111. As shown in FIG. 30, thecontact holes 104 may be arranged parallel to the first-1 branches andthe first conductive type semiconductor layer 111 may be exposed in acircular shape through the contact holes 104. However, it should beunderstood that the shape and arrangement of the contact holes are notlimited thereto. Further, in the partially exposed region of the firstconductive type semiconductor layer 111, a mesa including the secondconductive type semiconductor layer 113 and the active layer 112 may beformed by partially removing the second conductive type semiconductorlayer 113 and the active layer 112. A side surface of the secondconductive type semiconductor layer 113 and a side surface of the activelayer 112 disposed around the contact holes 104 may include inclinedside surfaces. The inclined side surfaces of the contact holes 104improve extraction efficiency of light generated in the active layer112. Although not shown in the drawings, a buffer layer may be formedbetween the first conductive type semiconductor layer 111 and asubstrate 100, and may be an undoped semiconductor layer composed of anitride and the like in order to relieve lattice mismatch between thefirst conductive type semiconductor layer 111 and the second conductivetype semiconductor layer 113. The plurality of contact holes 104increase the area and number of contact regions between a contact-holeconnection 101 and the first conductive type semiconductor layer 111,thereby enabling effective current spreading.

Referring to FIG. 32 and FIG. 33, the pre-insulation layer 114 may covera portion of the second conductive type semiconductor layer 113 disposedaround the contact holes 104 and a portion of the first conductive typesemiconductor layer 111 exposed through the contact holes 104. Thepre-insulation layer 114 may include an opening, which defines regionsin which first to third electrode connections 150, 250, 350 will bedisposed. The pre-insulation layer 114 can prevent damage to the secondconductive type semiconductor layer 113 by an etchant such as a bufferedoxide etchant (BOE) upon formation of the first to third electrodeconnections 150, 250, 350.

The pre-insulation layer 114 may include an insulation material, forexample, SiO₂, SiN_(x), MgF₂, and the like. The pre-insulation layer 114may act as a basal layer with respect to other layers formed on thepre-insulation layer 114. For example, in the structure wherein thefirst insulation layer 116 described below includes a distributed Braggreflector, the pre-insulation layer 114 may act as a basal layer thatenables stable formation of the distributed Bragg reflector, therebyminimizing generation of cracks in the distributed Bragg reflector whileimproving resistance to electrostatic discharge (ESD). In the structurewherein the distributed Bragg reflector has a multilayer structure ofTiO₂/SiO₂ layers alternately stacked one above another, thepre-insulation layer 114 may be formed of a SiO₂ layer having apredetermined thickness or more. For example, the thickness may rangefrom about 0.2 μm to 1.0 μm. In order to form a high quality distributedBragg reflector, it is desirable that the basal layer for thedistributed Bragg reflector have good quality and surface properties.Accordingly, the pre-insulation layer 114 is formed to the predeterminedthickness or more, thereby enabling stable formation of the distributedBragg reflector on the pre-insulation layer 114.

Referring to FIG. 32 and FIG. 33, the contact electrode 115 is disposedon the second conductive type semiconductor layer 113 and may cover mostof the second conductive type semiconductor layer 113 around the contactholes 104 excluding a region in which the pre-insulation layer 114covers the second conductive type semiconductor layer 113. The contactelectrode 115 may serve to form ohmic contact with the second conductivetype semiconductor layer 113 while reflecting light. Thus, the contactelectrode 115 may include a metal having high reflectance and capable offorming ohmic contact with the second conductive type semiconductorlayer 113. For example, the contact electrode 115 may include at leastone of Ni, Pt, Pd, Rh, W, Ti, Al, Ag, Au, and ITO/ZnO. Further, thecontact electrode 115 may include a single layer or multiple layers.

The first insulation layer 116 may be disposed on the upper surfaces ofthe first conductive type semiconductor layer 111, the active layer 112,and the second conductive type semiconductor layer 113 in regions of thecontact electrode 115 and the contact holes 104. In the structurewherein the light emitting element includes the pre-insulation layer114, the first insulation layer 116 is disposed on the pre-insulationlayer 114 and may cover at least a portion of the contact electrode 115.The first insulation layer 116 insulates the contact electrode 115 fromthe contact-hole connection 101 and serves to protect the first andsecond conductive type semiconductor layers 111, 113 from foreign mattersuch as moisture. Referring to an enlarged circle of FIG. 30, the firstinsulation layer 116 has an opening 116 a, through which the first-1electrode connection 140 is electrically connected to the contactelectrode 115, in the region of the first-1 electrode connection 140.The opening 116 a may have a narrower width than the first-1 branches103. Furthermore, a lower surface of the second-1 electrode connection240 of the second light emitting cell 200 and a lower surface of thethird-1 electrode connection 340 of third light emitting cell 300 areformed with openings of the first insulation layers 216, 316corresponding to the opening 116 a. The first insulation layer 116 mayinclude an oxide layer such as SiO₂, a nitride layer such as SiN_(x), oran insulation layer such as MgF₂. Further, the first insulation layer116 may include a distributed Bragg reflector (DBR) in which a lowrefractivity material layer and a high refractivity material layer arealternately stacked. For example, an insulation reflective layer havinghigh reflectance may be formed by stacking SiO₂/TiO₂ layers orSiO₂/Nb₂O₅ layers.

As shown in FIG. 30, the contact-hole connection 101 includescontact-hole connecting edge portions 130 disposed on edges of a portionof the third side surface, the second side surface, and a portion of thefourth side surface of the first light emitting cell 100, andcontact-hole connection branches 131 extending in a branch shape fromthe contact-hole connecting edge portions 130 to connect the contactholes 104. Referring to FIG. 30, the contact-hole connecting branches131 include branches extending from a contact-hole connecting edgeportion 130 disposed at a side of the second side surface of the firstlight emitting cell 100 towards the first side surface, branchesextending from a contact-hole connecting edge portion 130 disposed at aside of the second side surface thereof towards the third side surfacethereof, and branches extending from a contact-hole connecting edgeportion 130 disposed at a side of fourth side surface thereof towardsthe first side surface thereof. The contact-hole connecting branches 131may be parallel to each other.

The contact-hole connection 101 may be disposed on the first insulationlayer 116 and the first conductive type semiconductor layer 111 andelectrically connected to the first conductive type semiconductor layer111 through the contact holes 104 formed in first light emitting cell100. In addition, the contact-hole connection 101 may adjoin the firstelectrode pad 500 through first openings 105 of the second insulationlayer 117. That is, the contact-hole connection 101 may be formed toachieve electrical connection between the first electrode pad 500 andthe first conductive type semiconductor layer 111. Further, since thefirst openings 105 are alternately arranged between the contact holes104, and the first openings 105, the contact holes 104 and thecontact-hole connection 101 are disposed over the entire region of thefirst light emitting cell 100, electric current can be effectivelydispersed through electrical connection between the first electrode pad500 and the first conductive type semiconductor layer 111.

The contact-hole connection 101 and the first to third electrodeconnections 150, 250, 350 described below may include a highlyreflective metal layer such as an Al layer, and the highly reflectivemetal layer may be formed on a contact layer such as a Ti, Cr or Nilayer. Further, a protective layer composed of a single layer ormultiple layers of Ni, Cr, Au, and the like may be formed on the highreflective layer. The contact-hole connection 101 may include amultilayer structure of, for example, Ti/Al/Ti/Ni/Au layers. Thecontact-hole connection 101 may be formed by depositing a metallicmaterial, followed by patterning, without being limited thereto. Inaddition, the contact-hole connection 101 may be formed together withthe first to third electrode connections by the same process.

As shown in FIG. 32 and FIG. 33, the second insulation layer 117 may bedisposed on the contact-hole connection 101, the first insulation layer116, and the first-1 electrode connection 140. The second insulationlayer 117 may serve to prevent disconnection of the contact electrode115, the contact-hole connection 101 and the first-1 electrodeconnection 140 from the first electrode pad 500 while protecting thelight emitting structure from foreign matter or impact. The secondinsulation layer 117 may include an oxide layer such as SiO₂, a nitridelayer such as SiN_(x), an insulation layer such as MgF₂, or polymerssuch as polyimide, Teflon, and Parylene. In addition, the firstinsulation layer 116 may include a distributed Bragg reflector (DBR) inwhich a low refractivity material layer and a high refractivity materiallayer are alternately stacked. For example, an insulation reflectivelayer having high reflectance may be formed by stacking SiO₂/TiO₂ layersor SiO₂/Nb₂O₅ layers.

The second insulation layer 117 may include openings 105 through whichthe first electrode pad and the second electrode pad are electricallyconnected to the first conductive type semiconductor layer 111 andopenings 402 through which the first electrode pad and the secondelectrode pad are electrically connected to the second conductive typesemiconductor layer 113. The openings 105 may be formed in regionsbetween the contact holes 104 of the first light emitting cell 100 andthe openings 402 may be formed in regions between the contact holes ofthe fourth light emitting cell.

As shown in FIG. 30, the first-1 electrode connection 140 includes thefirst-1 edge portions 102 and the first-1 branches 103. The first-1electrode connection 140 serves to electrically connect the firstintermediate connection 106 to the second conductive type semiconductorlayer 113 of the first light emitting cell 100. The first-1 edgeportions 102 may include an edge portion placed at a portion of thethird side surface of the first light emitting cell 100 and an edgeportion placed at an edge of the first side surface thereof. The first-1branches 103 include branches extending from the first-1 edge portion102 disposed at a side of the third side surface towards the second sidesurface, branches extending from the first-1 edge portion 102 disposedat a side of the first side surface towards the second side surface, andbranches extending from the first-1 edge portion 102 disposed at a sideof the first side surface towards the fourth side surface. With thisstructure of the first-1 electrode connection 140, a contact regionbetween the first-1 electrode connection 140 and the contact electrode115 of the first light emitting cell has a wide area and is distributedthroughout the first light emitting cell 100. As a result, the firstlight emitting cell 100, the second light emitting cell 200, and thethird and fourth light emitting cells 300, 400 described below areconnected to each other in series and have constant forward voltagecharacteristics, thereby improving reliability of the light emittingelement.

The plural first-1 branches 103 may be disposed parallel to each otherbetween the contact holes 104 of the first light emitting cell 100.Although the contact-hole connection 101 does not adjoin the first-1electrode connection 140, the branches of the contact-hole connection101 and the first-1 electrode connection 140 may be alternately arrangedto be adjacent to one another.

The first intermediate connection 106 is a portion of the firstelectrode connection 150 disposed in a region between the first lightemitting cell 100 and the second light emitting cell 200 and serves toconnect the first-1 electrode connection 140 to the first-2 electrodeconnection 160.

As shown in FIG. 30 and FIG. 34, the first-2 electrode connection 160may be disposed on the first insulation layer 216 and a first conductivetype semiconductor layer 211 of the second light emitting cell 200, andincludes first-2 edge portions 201 and first-2 branches 202. The first-2edge portions 201 are disposed on a portion of the first side surface ofthe second light emitting cell 200 and edges of the fourth side surfacethereof. The first-2 branches 202 include branches extending from thefirst-2 edge portions 201 disposed at a side of the first side surfacetowards the third side surface, branches extending from the first-2 edgeportions 201 disposed at a side of the first side surface towards thesecond side surface, and the first-2 branches 202 extending from thefirst-2 edge portions 201 disposed at a side of the fourth side surfacetowards the second side surface.

The plural first-2 branches 202 may be disposed parallel to each otherand connect the contact holes 104 of the second light emitting cell 200to each other. Although the first-2 branches 202 do not adjoin thesecond-1 branches 204, these branches may be alternately arranged to beadjacent to one another.

The plural first-2 branches 202 may be disposed parallel to the pluralfirst-1 branches 103, and the first-2 branches 202 and the first-1branches 103 may be inclined with respect to the first direction 1 and aperpendicular direction to the first direction 1.

The first-2 electrode connection 160 serves to connect the firstconductive type semiconductor layer 211 of the second light emittingcell 200 to the first intermediate connection 106. That is, the first-1electrode connection 140, the first intermediate connection 106, and thefirst-2 electrode connection 160, which constitute the first electrodeconnection 150, serve to electrically connect the first conductive typesemiconductor layer 211 of the second light emitting cell 200 to thesecond conductive type semiconductor layer 113 of first light emittingcell 100, and the branches thereof deeply extend to the cell regionsthereof, thereby improving current spreading performance.

The contact holes 104, the first conductive type semiconductor layers211, 311, the active layers 212, 312, the second conductive typesemiconductor layer 213, 313, the contact electrodes 215, 315, the firstinsulation layers 216, 316 and the second insulation layers 217, 317 ofthe second light emitting cell 200 and the third light emitting cell 300have the same features and functions as those of the first lightemitting cell 100 except that the second insulation layers 217, 317 donot include the openings 105. Further, corresponding to the firstelectrode connection 150, the second electrode connection 250electrically connecting the second light emitting cell 200 to the thirdlight emitting cell 300 also includes the second-1 electrode connection240, the second intermediate connection 205 and the second-2 electrodeconnection 260, which have the same features and functions as thefirst-1 electrode connection 140, the first intermediate connection 105and the first-2 electrode connection 160, respectively.

As shown in FIG. 30, FIG. 36 and FIG. 37, the third electrode connection350 electrically connects the third light emitting cell 300 to thefourth light emitting cell 400. The features and functions of thethird-1 electrode connection 340 and the third intermediate connection305 are the same as those of the first-1 electrode connection 140 andthe first intermediate connection 105. However, the third-2 electrodeconnection 401 is different from the first-2 and second-2 electrodeconnections 160, 260 in that the third-2 electrode connection 401 isformed in the entire region of the fourth light emitting cell 400.

Referring to FIG. 36 and FIG. 37, the fourth light emitting cell 400includes a first conductive type semiconductor layer 411, an activelayer 412 disposed on the first conductive type semiconductor layer 411,and a second conductive type semiconductor layer 413 disposed on theactive layer 412. Further, the fourth light emitting cell 400 includes apre-insulation layer 414, a contact electrode 415, a first insulationlayer 416, a second insulation layer 417, and a plurality of contactholes 104 through which the first conductive type semiconductor layer411 is partially exposed so as to be connected to the third-2 electrodeconnection 401. The features of the contact holes 104 of the fourthlight emitting cell 400 are the same as those of the contact holes 104of the first to third light emitting cells 100, 200, 300.

Further, the fourth light emitting cell 400 includes a partially exposedregion of the contact electrode 415 formed by partially removing thefirst insulation layer 416, the third-2 electrode connection 401 and thesecond insulation layer 417. For example, as shown in FIG. 30 and FIG.37, a plurality of openings 402 may be disposed on the fourth lightemitting cell 400 so as to expose the contact electrode 415 such that asecond electrode pad 600 is electrically connected to the contactelectrode 415 therethrough. The second electrode pad 600 may beelectrically connected to the second conductive type semiconductor layer413 through the contact electrode 415. As shown in FIG. 30, the contactelectrode 415 may be exposed in a circular shape through the openings402 arranged between the contact holes 104 formed in the fourth lightemitting cell 400. However, it should be understood that the shape andarrangement of the openings are not limited thereto.

As shown in FIG. 31, the first electrode pad 500 is disposed on thefirst and second light emitting cells 100, 200 and the second electrodepad 600 is disposed on the third and fourth light emitting cells 300,400. The first electrode pad 500 may be electrically connected to thecontact-hole connection 101 through the openings 105 disposed on thefirst light emitting cell 100 and electrically connected to the firstconductive type semiconductor layer 111 through the contact-holeconnection 101. The second electrode pad 600 may be electricallyconnected to the contact electrode 415 through the openings 402 disposedon fourth light emitting cell 400 and electrically connected to thesecond conductive type semiconductor layer 413 through the contactelectrode 415.

Each of the first electrode pad 500 and the second electrode pad 600 maybe composed of a single layer or multiple layers and may include anelectrically conductive material. For example, each of the firstelectrode pad 500 and the second electrode pad 600 may include at leastone of Cu, Pt, Au, Ti, Ni, Al and Ag, and may also include sinteredmetal particles and non-metallic materials interposed between metalparticles. Here, the first electrode pad 500 and the second electrodepad 600 may be formed by plating, deposition, dotting, screen-printing,and the like.

A distance between the first electrode pad 500 and the second electrodepad 600 may be 80 μm or less. With the structure wherein the firstelectrode pad 500 and the second electrode pad 600 cover the mostregions of the first and second light emitting cells 100, 200 and thethird and fourth light emitting cells 300, 400, the first electrode pad500 and the second electrode pad 600 can provide improved bondingstrength and good heat dissipation.

FIG. 38 and FIG. 39 are a cross-sectional view and a plan view of amodule including the light emitting element according to the twelfthexemplary embodiment of the present disclosure.

The module may be applied to a headlamp for vehicles. The module mayinclude the light emitting element 1000 described above, first andsecond electrode pads 500, 600, first and second conductive patterns1001 a, 1001 b formed at a lower side of the light emitting element,first and second heat sinks 1002 a, 1002 b, a lower base 1003, an upperbase 1004, a cavity 1006, and bonding wires 1005 a, 1005 b, 1005 c, 1005d.

The first conductive pattern 1001 a and the second conductive pattern1001 b are separated from each other on the lower base 1003. Some of thefirst conductive pattern 1001 a and the second conductive pattern 1001 bmay be exposed from the cavity 1006 defined by the upper base 1004 so asto be freely connected to an external component. The upper base 1004 isdisposed on the lower base 1003 and may be formed on the first andsecond conductive patterns 1001 a, 1001 b such that some of the firstand second conductive patterns 1001 a, 1001 b are exposed. An inner wallof the upper base 1004, that is, a wall adjoining the cavity 1006, maybe inclined. With this structure, the inner wall of the upper base 1004reflects light emitted from the light emitting element 1000, therebyimproving luminous efficacy of the module.

The first and second heat sinks 1002 a, 1002 b are disposed under thecavity 1004. The first and second heat sinks 1002 a, 1002 b are exposedfrom a lower surface of the lower base 1003 through the lower base 1003.The first and second electrode pads 500, 600 are connected to the firstand second heat sinks 1002 a, 1002 b, respectively.

The bonding wires 1005 a, 1005 b connect the first and second heat sinks1002 a, 1002 b to the first and second conductive patterns 1001 a, 1001b, respectively. Thus, the first and second electrode pads 500, 600 areelectrically connected to the first and second conductive patterns 1001a, 1001 b through the first and second heat sinks 1002 a, 1002 b and thebonding wires 1005 a, 1005 b. The heat sink 1002 a, 1002 b may include ametal or metal alloy, particularly, a metal or metal alloy having highthermal conductivity. For example, the heat sinks 1002 a, 1002 b mayinclude Cu, Al, and alloys of Cu and Al. An external voltage is appliedto the first and second conductive patterns 1001 a, 1001 b through thebonding wires 1005 c, 1005 d, and then is applied to the first andsecond heat sinks 1002 a, 1002 b through the bonding wires 1005 a, 1005b.

The cavity 1006 may be filled with a potting material, for example,silicone, and protect the light emitting element 1000 from externalenvironments. Furthermore, phosphors may be disposed in the cavity 1006or on the light emitting element in a predetermined pattern.

As such, the light emitting element according to the exemplaryembodiments may be applied to the module according to the exemplaryembodiment, particularly, a headlamp for vehicles, thereby improvingreliability of the headlamp.

FIG. 40 is an exploded perspective view of a lighting apparatus to whicha light emitting element according to one exemplary embodiment of thepresent disclosure is applied.

Referring to FIG. 40, the lighting apparatus according to thisembodiment includes a diffusive cover 1010, a light emitting elementmodule 1020, and a body 1030. The body 1030 may receive the lightemitting element module 1020 and the diffusive cover 1010 may bedisposed on the body 1030 to cover an upper side of the light emittingelement module 1020.

The body 1030 may have any shape so long as the body can supply electricpower to the light emitting element module 1020 while receiving andsupporting the light emitting element module 1020. For example, as shownin the drawing, the body 1030 may include a body case 1031, a powersupply 1033, a power supply case 1035, and a power source connection1037

The power supply 1033 is received in the power supply case 1035 to beelectrically connected to the light emitting element module 1020, andmay include at least one IC chip. The IC chip may regulate, change orcontrol electric power supplied to the light emitting element module1020. The power supply case 1035 may receive and support the powersupply 1033. The power supply case 1035 having the power supply 1033secured therein may be disposed within the body case 1031. The powersource connection 1037 is disposed at a lower end of the power supplycase 1035 and is coupled thereto. Accordingly, the power sourceconnection 1037 is electrically connected to the power supply 1033within the power supply case 1035 and may serve as a passage throughwhich power can be supplied from an external power source to the powersupply 1033.

The light emitting element module 1020 includes a substrate 1023 and alight emitting element 1021 disposed on the substrate 1023. The lightemitting element module 1020 may be disposed at an upper portion of thebody case 1031 and electrically connected to the power supply 1033.

As the substrate 1023, any substrate capable of supporting the lightemitting element 1021 may be used without limitation. For example, thesubstrate 1023 may include a printed circuit board having interconnectsformed thereon. The substrate 1023 may have a shape corresponding to asecuring portion formed at the upper portion of the body case 1031 so asto be stably secured to the body case 1031. The light emitting element1021 may include at least one of the light emitting elements accordingto the exemplary embodiments described above.

The diffusive cover 1010 is disposed on the light emitting element 1021and may be secured to the body case 1031 to cover the light emittingelement 1021. The diffusive cover 1010 may be formed of alight-transmitting material and light orientation of the lightingapparatus may be adjusted through regulation of the shape and opticaltransmissivity of the diffusive cover 1010. Thus, the diffusive cover1010 may be modified in various shapes depending on usage andapplications of the lighting apparatus.

FIGS. 41A and 41B are cross-sectional views of one example of a displayapparatus to which a light emitting element according to one exemplaryembodiment of the present disclosure is applied.

The display according to this embodiment includes a display panel 2110,a backlight unit BLU1 supplying light to the display panel 2110, and apanel guide 2100 supporting a lower edge of the display panel 2110.

The display panel 2110 is not particularly limited and may be, forexample, a liquid crystal panel including a liquid crystal layer. Gatedriving PCBs may be further disposed at the periphery of the displaypanel 2110 to supply driving signals to a gate line. Here, the gatedriving PCBs 2112, 2113 may be formed on a thin film transistorsubstrate instead of being formed on separate PCBs.

The backlight unit BLU1 includes a light source module, which includesat least one substrate 2150 and a plurality of light emitting elements2160. The backlight unit BLU1 may further include a bottom cover 2180, areflective sheet 2170, a diffusive plate 2131, and optical sheets 2130.

The bottom cover 2180 may be open at an upper side thereof to receivethe substrate 2150, the light emitting elements 2160, the reflectivesheet 2170, the diffusive plate 2131, and the optical sheets 2130. Inaddition, the bottom cover 2180 may be coupled to the panel guide 2100.The substrate 2150 may be disposed under the reflective sheet 2170 to besurrounded by the reflective sheet 2170. Alternatively, when areflective material is coated on a surface thereof, the substrate 2150may be disposed on the reflective sheet 2170. Further, a plurality ofsubstrates 2150 may be arranged parallel to one other, without beinglimited thereto. However, it should be understood that the light sourcemodule may include a single substrate.

The light emitting elements 2160 may include at least one of the lightemitting elements according to the exemplary embodiments describedabove. The light emitting elements 2160 may be regularly arranged in apredetermined pattern on the substrate 2150. In addition, a lens 2210may be disposed on each of the light emitting elements 2160 to improveuniformity of light emitted from the plurality of light emittingelements 2160.

The diffusive plate 2131 and the optical sheets 2130 are disposed on thelight emitting element 2160. Light emitted from the light emittingelement 2160 may be supplied in the form of sheet light to the displaypanel 2110 through the diffusive plate 2131 and the optical sheets 2130.

In this way, the light emitting elements according to the exemplaryembodiments may be applied to direct type displays like the displayaccording to this embodiment.

FIGS. 42A and 42B are cross-sectional views of another example of thedisplay apparatus to which the light emitting element according to theexemplary embodiment of the present disclosure is applied.

The display according to this exemplary embodiment includes a displaypanel 3210 on which an image is displayed, and a backlight unit BLU2disposed at a rear side of the display panel 3210 and emitting lightthereto. Further, the display includes a frame 240 supporting thedisplay panel 3210 and receiving the backlight unit BLU2, and covers3240, 3280 surrounding the display panel 3210.

The display panel 3210 is not particularly limited and may be, forexample, a liquid crystal panel including a liquid crystal layer. A gatedriving PCB may be further disposed at the periphery of the displaypanel 3210 to supply driving signals to a gate line. Here, the gatedriving PCB may be formed on a thin film transistor substrate instead ofbeing formed on a separate PCB. The display panel 3210 is secured by thecovers 3240, 3280 disposed at upper and lower sides thereof, and thecover 3280 disposed at the lower side of the display panel 3210 may becoupled to the backlight unit BLU2.

The backlight unit BLU2 supplying light to the display panel 3210includes a lower cover 3270 partially open at an upper side thereof, alight source module disposed at one side inside the lower cover 3270,and a light guide plate 3250 disposed parallel to the light sourcemodule and converting spot light into sheet light. In addition, thebacklight unit BLU2 according to this exemplary embodiment may furtherinclude optical sheets 3230 disposed on the light guide plate 3250 tospread and collect light, and a reflective sheet 3260 disposed at alower side of the light guide plate 3250 and reflecting light travelingin a downward direction of the light guide plate 3250 towards thedisplay panel 3210.

The light source module includes a substrate 3220 and a plurality oflight emitting elements 3110 arranged at constant intervals on onesurface of the substrate 3220. As the substrate 3220, any substratecapable of supporting the light emitting elements 3110 and beingelectrically connected thereto may be used without limitation. Forexample, the substrate 3220 may include a printed circuit board. Thelight emitting elements 3110 may include at least one of the lightemitting elements according to the exemplary embodiments describedabove. Light emitted from the light source module enters the light guideplate 3250 and is supplied to the display panel 3210 through the opticalsheets 3230. The light guide plate 3250 and the optical sheets 3230convert spot light emitted from the light emitting elements 3110 intosheet light.

In this way, the light emitting elements according to the exemplaryembodiments may be applied to edge type displays like the displayaccording to this exemplary embodiment.

FIG. 43 is a cross-sectional view of a headlight to which a lightemitting element according to one exemplary embodiment of the presentdisclosure is applied.

Referring to FIG. 43, the headlight according to this exemplaryembodiment includes a lamp body 4070, a substrate 4020, a light emittingelement 4010, and a cover lens 4050. The headlight may further include aheat dissipation unit 4030, a support rack 4060, and a connection member4040.

The substrate 4020 is secured by the support rack 4060 and is disposedabove the lamp body 4070. As the substrate 4020, any member capable ofsupporting the light emitting element 4010 may be used withoutlimitation. For example, the substrate 4020 may include a substratehaving a conductive pattern, such as a printed circuit board. The lightemitting element 4010 is disposed on the substrate 4020 and may besupported and secured by the substrate 4020. In addition, the lightemitting element 4010 may be electrically connected to an external powersource through the conductive pattern of the substrate 4020. Further,the light emitting element 4010 may include at least one of the lightemitting elements according to the exemplary embodiments describedabove.

The cover lens 4050 is disposed on a path of light emitted from thelight emitting element 4010. For example, as shown in the drawing, thecover lens 4050 may be spaced apart from the light emitting element 4010by the connection member 4040 and may be disposed in a direction ofsupplying light emitted from the light emitting element 4010. By thecover lens 4050, an orientation angle and/or a color of light emitted bythe headlight can be adjusted. On the other hand, the connection member4040 is disposed to secure the cover lens 4050 to the substrate 4020while surrounding the light emitting element 4010, and thus may act as alight guide that provides a luminous path 4045. The connection member4040 may be formed of a light reflective material or coated therewith.On the other hand, the heat dissipation unit 4030 may include heatdissipation fins 4031 and/or a heat dissipation fan 4033 to dissipateheat generated upon operation of the light emitting element 4010.

In this way, the light emitting diodes according to the exemplaryembodiment may be applied to headlights, particularly, headlights forvehicles, like the headlight according to this embodiment.

Although some exemplary embodiments are disclosed herein, it should beunderstood that these embodiments are not intended to be exclusive. Forexample, individual structures, elements or features of a particularembodiment are not limited to that particular embodiment and can beapplied to other embodiments without departing from the spirit and scopeof the present disclosure.

The invention claimed is:
 1. A light emitting element comprising: afirst light emitting cell; a second light emitting cell disposedcoplanar with the first light emitting cell and electrically connectedto the first light emitting cell in series; and an electrode connectionelectrically connecting the first light emitting cell to the secondlight emitting cell, wherein the electrode connection comprises: a firstelectrode connection disposed on the first light emitting cell; a secondelectrode connection disposed on the second light emitting cell; and anintermediate connection interposed between the first light emitting celland the second light emitting cell, wherein the second electrodeconnection comprises an edge portion extending from the intermediateconnection and a plurality of branches branched off from the edgeportion, wherein the branches branched off from the edge portionincludes a first branch and a second branch that are arranged inparallel and have different lengths from each other.
 2. The lightemitting element according to claim 1, wherein the second light emittingcell is disposed adjacent to the first light emitting cell in a firstdirection, and wherein a width of the edge portion in a second directionvertical to the first direction is larger than a width of each branch inthe second direction, wherein the second direction is vertical to thefirst direction in a plan view of the light emitting element.
 3. Thelight emitting element according to claim 2, wherein a width of theintermediate connection in the second direction is substantially same asthe width of the edge portion in the second direction.
 4. The lightemitting element according to claim 3, wherein the intermediateconnection substantially covers an entire region between the first lightemitting cell and the second light emitting cell.
 5. The light emittingelement according to claim 1, wherein each of the first light emittingcell and the second light emitting cell comprises: a first conductivetype semiconductor layer; a second conductive type semiconductor layer;and an active layer interposed between the first conductive typesemiconductor layer and the second conductive type semiconductor layer;wherein the first electrode connection is electrically connected to thesecond conductive type semiconductor layer of the first light emittingcell, and the second electrode connection is electrically connected tothe first conductive type semiconductor layer of the second lightemitting cell.
 6. The light emitting element according to claim 5,wherein the second light emitting cell comprises contact holes exposingthe first conductive type semiconductor layer through the secondconductive type semiconductor layer and the active layer, and whereinthe plurality of branches are electrically connected to the firstconductive type semiconductor layer through the contact holes.
 7. Thelight emitting element according to claim 6, wherein each of the firstand second light emitting cells further comprises a contact electrodedisposed on and forming ohmic contact with the second conductive typesemiconductor layer, and wherein the first electrode connection iselectrically connected to the contact electrode of the first lightemitting cell.
 8. The light emitting element according to claim 7,further comprising an insulation layer covering the contact electrode,wherein the insulation layer has an opening exposing the contactelectrode of the first light emitting cell, and wherein the firstelectrode connection is connected to the contact electrode through theopening of the insulation layer.
 9. The light emitting element accordingto claim 8, wherein the insulation layer has openings exposing the firstconductive type semiconductor layer in the contact holes, and whereinthe plurality of branches of the second electrode connection areconnected to the first conductive type semiconductor layer through theopenings of the insulation layer.
 10. The light emitting elementaccording to claim 1, wherein the plurality of branches have the samewidth as one another.
 11. A light emitting element comprising: asubstrate; a first light emitting cell disposed on the substrate; asecond light emitting cell disposed on the substrate and spaced apartfrom the first light emitting cell by a separation region in a firstdirection; and an electrode connection electrically connecting the firstlight emitting cell to the second light emitting cell, wherein theseparation region exposes the substrate, wherein the electrodeconnection comprises: a first electrode connection disposed on the firstlight emitting cell; a second electrode connection disposed on the firstlight emitting cell; and an intermediate connection disposed on theseparation region, wherein the second electrode connection comprises aplurality of branches, and a width of the intermediate connection in asecond direction is larger than a sum of the widths of the plurality ofbranches in the second direction, wherein the second direction isvertical to the first direction in a plan view of the light emittingelement.
 12. The light emitting element according to claim 11, whereinthe second electrode connection further comprises an edge portionextending from the intermediate connection, and wherein the plurality ofbranches extend from the edge portion.
 13. The light emitting elementaccording to claim 12, wherein a width of the edge portion in the seconddirection is substantially same as the width of the intermediateconnection in the second direction.
 14. The light emitting elementaccording to claim 11, wherein each of the first light emitting cell andthe second light emitting cell comprises: a first conductive typesemiconductor layer; a second conductive type semiconductor layer; andan active layer interposed between the first conductive typesemiconductor layer and the second conductive type semiconductor layer;wherein the first electrode connection is electrically connected to thesecond conductive type semiconductor layer of the first light emittingcell, and the second electrode connection is electrically connected tothe first conductive type semiconductor layer of the second lightemitting cell.
 15. The light emitting element according to claim 14,wherein the second light emitting cell comprises contact holes exposingthe first conductive type semiconductor layer through the secondconductive type semiconductor layer and the active layer, and whereinthe branches are electrically connected to the first conductive typesemiconductor layer through the contact holes.
 16. The light emittingelement according to claim 15, wherein each of the first and secondlight emitting cells further comprises a contact electrode disposed onand forming ohmic contact with the second conductive type semiconductorlayer, and wherein the first electrode connection is electricallyconnected to the contact electrode of the first light emitting cell. 17.The light emitting element according to claim 16, further comprising aninsulation layer covering the contact electrode, wherein the insulationlayer has an opening exposing the contact electrode of the first lightemitting cell, and wherein the first electrode connection is connectedto the contact electrode through the opening of the insulation layer.18. The light emitting element according to claim 17, wherein theinsulation layer has openings exposing the first conductive typesemiconductor layer in the contact holes, and wherein the plurality ofbranches of the second electrode connection are connected to the firstconductive type semiconductor layer through the openings of theinsulation layer.
 19. The light emitting element according to claim 11,wherein the plurality of branches have the same width as one another.20. The light emitting element according to claim 11, wherein theintermediate connection substantially covers the separation regionbetween the first light emitting cell and the second light emittingcell.